First duty station as Yongsan? does this mean that I am going to Yongsan, but all my battle's say Camp Henry? Why mine not pinpointed?

Not to mention Camp Humphreys up near Osan, AB.
However, if it is still like it was back when I was stationed at Osan. A lot of troops that were stationed down near Kunsan would come up to Osan when they got a break. There is a city right outside of the main gate, it called Songtan City. At night, it has night after night. Such as "My House Up" & "My House Down". Those are two that I can remember. Its best trait is, during the daytime it is the largest yardsale I've ever seen. Seriously you can get some pretty good stuff made from brass, leather and other things at very low prices.
As far as food, I recommend Bulgogi on Rice (with a little soy sauce on it) and Yaki Mandu. But one word of warning, Yakima Mandy is best if eaten while warm or hot, NEVER cold.

Aside from the Camp though, what does the assigned unit on your orders say? Are the other individuals assigned to the same unit, but at Camp Henry or do your orders have different units and different Camps? If your orders say 1st Replacement Company, or 2nd Infantry Division then you have a generic assignment just getting you into Korea and then will be reassigned to your unit once you arrive. The other guys might have a pinpoint assignment to another Major Subordinate Command (MSC) that is Headquartered at Camp Henry, but it's possible that they could be further reassigned as well. Even the guys with Camp Henry on their orders will go to Yongsan and stay there for a couple night until they finish their initial Korea in-processing and then will move to their assigned areas. Also, once you arrive in theater you can be reassigned anywhere within the theater based on their needs for your MOS (not necessarily what your orders say). It is unusual for lower enlisted to get pinpoint orders to their actual unit unless you have a unique MOS.