Can officers in the reserves or guard take corresponding courses for additional retirement points?

Most definitely! There's a number of ways these can be tracked. Your unit's Training NCO/FTUS Readiness NCO should be able to tell you how. There's a DA form associated with it, I just can't remember which one.

Yes. I did ILE entirely by correspondence (UGH) and got something like 150 points for it.

As others have said, yes. If you do them through ACCP, the points should show up "automagically" at the rate of 1 point per 3 "study hours". If you do non-ACCP, make sure it is properly tracked and recorded (1380, or whatever the process is now).

NOTE: Do NOT dispose of subcourse completion notices until you see the points credited. I spent several years "proving" my points for the DL version of ILE to the points people, despite having the 1059 in my possession.

Yes, ask your UA as you can get paid for some too. Be careful though as you can do a max each year for points.

As a couple of people have mentioned, some of the courses you can also get paid for, but you are supposed to have pre-approval before you take the course. There is a course list of available Electronic Based Distance Learning (EBDL), http://www.ezarmypoints.com/wp-content/uploads/2014/08/EBDLcourses.pdf

Here is the link on HRC that discusses different types of points and maximum you can earn. https://www.hrc.army.mil/TAGD/Earning%20Retirement%20Points

Under the Army Correspondence Course Program, you can find a list of courses available. https://www.atsc.army.mil/tadlp/accp/index.asp

For the DoD Instruction 1215.21, Reserve Component (RC) Use of Electronic-based Distributed Learning Methods for Training, that authorizes this for the Reserve Components, http://www.dtic.mil/whs/directives/corres/pdf/121521p.pdf

Excellent question 1LT A. Uribe. LTC (Join to see) is on point here.
Thought this one would be a great one for Capt Craig Gilman, GySgt George Vukovich, and PO3 John Aldrich to see.

*Update* Did a little research on this and this is what I have. Do not know if this is the same for USAR or not.

For NG. You are allowed 130 points TOTAL for a year. 63 of those points are for drills(48 UTA's and 15 days of AT) that leaves 67 points(1 point for every 3 hrs of courseware). You can go thru either ALMS or ATRRS, but DO NOT do the E-Learning courses. NGB states they do not count at this time. Once you complete the course bring your cerificate to your FTM, and they will send to your RPAM NCO who will key them into your RPAM.
1LT A. Uribe
LTC (Join to see)
COL Vincent Stoneking
1SG (Join to see)
MAJ (Join to see)

One of the Officers in my unit just finished his DL portion of Captain Career Course and got paid and retirement points

I had seen what you had asked, and had a couple of thoughts I didn't know if you might possibly care to consider, for whatever they might be worth. A couple of relatively little-known possibilities that might have been ones you might not have stumbled across are courses offered through both the Civil Air Patrol (CAP), e.g, the various CAP staff colleges, as well as the USCG Auxiliary. Also, the possibility of doing extension, correspondence, and/or online courses through the other services; one specific example I was aware of, at least from some years ago, was the USMC Command and Staff extension program through Marine Corps Institute (MCI), and I knew of a realy serious grad-level program given in extension through Naval War College (NWC), Newport, RI, at least many years ago. Now, also, having said that, I did actually read online at one point that USCG Auxiliary has some sort of college-based and/or university-styled training program, I believe called the USCG Auxiliary University Program (AUP); also, I did actually see mentioned online that they were able, in some fashion, to fund though I am uncertain as to more, some sort of quite-possibly in-residence (at least in part, if not in full) masters program, for their members, given somewhere near Naval Postgraduate School (NPS) in California, at least awhile back. I believe I saw that a thesis is, or was, typically done for that masters program on a topic of direct relevance to the USCG Auxiliary. However, I must emphasize that I only read about purely in passing, as well as quite some time ago, and have absolutely no idea if it is still actually operating, and/or what the conditions and/or provisions for it might be, only that I had definitely seen something about it some time back online. If it is still existing, there is quite probably a really long waiting list for it, in all likelihood, as well as, most likely, some really serious time investment required, I would expect, as a USCG Auxiliary member, before one might actually be allowed to do it, though, of course, that is purely a guess on my part, obviously. I do also recall seeing that FEMA, and I think, the Natl. Fire Academy, had some sort of online program, possibly done in conjunction with regular colleges and/or universities. Whether such training might actually be creditable in some fashion, I obviously have no idea; however, I should certainly think it might be at least documentable in some fashion, possibly on performance reports, if nothing else, which I only offer as food for thought, if you will. My wife and I hope you and/or others here found the foregoing of at least some potential interest; should you and/or they care to here any further thoughts, we would obviously be most eager to hear as well. In any event, a nice holiday and new year to everyone, as well, by all means, of course.

Sounds like personal experience is meeting the propagation of "made up stuff." Let's defer to an SME like SFC (Join to see) accurate AND timely information.