When an E-4 calls me "hey" or "hey man" knowing that I am an officer, should I bother to correct him?

Yes. If the E-4 KNOWS that you are an officer, then proper military courtesy should be observed no matter where or when it happens. I can only remember one occasion where this was an issue during my career... A fellow NCO completed his college degree and went on to receive a commission. He came back to duty as a 2nd Lt before being reassigned to another base. We had worked together as equal ranks for nearly two years, and it was hard to remember to call him "Sir" when we were on duty.

If he knows that you are an officer, then proper military courtesy should be observed, no matter when or where it happens.

Hell yes just like in the Marine Corps when a Marine calls you SARG eat them alive. Same with Officers in any branch there is a rank respect it.

Outside of work I don't think it matters if the SPC doesn't call you Sir. However on base or a military setting a SPC needs to show Respect.

As long as he gives you the respect due to you in uniform, and on duty, I would give him enough respect to correct in private. Even when you're partying with him, enlisted know what we know. Respect all and it doesn't become an issue.

Yes.

Yes, it is appropriate to correct the individual. He should be upheld to military standards.

I can kind of understand if this individual had just came home from war time overseas tour? I believe whole heartedly in earned respect, but being from the SF community i feel anything i have to say to this, i have on many occasions, failed to adhere to at some point in time during my AF career as a PJ.

Whether you are in uniform or not, if he is aware you are an officer he should address you as sir.

You say he did call you sir. I would guess that it would depend on the context of the "hey man" you say this is outside of work, where in the conversation did this happen? If in the middle of a discussion and he's already greeted you properly at the outset, I would tend to overlook it. If it was his initial greeting then I would address the issue, and remind him that the proper greeting was still required even in civilian situations. The situation obviously made you uncomfortable and question your response so a reminder of proper protocol is in order. Pull the E-4 aside at work and explain to him your discomfort with "Hey, or Hey Man" and tell him or her how you (and other officers) should be addressed in civilian off duty situations. In the Navy (the first 6 years of my military career) Overseas on a Navy destroyer it was common for us to run into our Captain or other officers out on the town when we pulled into a port. We would initially address him as Captain upon first seeing him, and he would often lighten the situation and say call me Bud (his well known nickname) out here, because he didn't want to draw civilian attention to himself. Military protocol is definately a good thing and should be followed, there are situations where it can be loosened, but it should be at the request of the senior member, and not something taken for granted by the lower ranked member.