Welcome to the site Matt!
Kaiser actually bought the rights to the Buick V6 in 1965 and started putting them in CJ's in 66 (I'm pretty sure). I'm sure yours does have a 225 v6 in it as it was a very popular engine. There is allot of information available on the WEB, but unfortunately about the best I know is down right now (Early CJ5). EarlyCJ5 has a great section on this great engine.
dauntless v6 site:earlycj5.com - Google Search
http://www.earlycj5.com/tech/engines/225/
As for what to watch out for? Since we don't know your experience level with CJ's or other off-road vehicles I'll make a simple list.
You need to demo it in 4wd and in 4wd low also. Also look for all the typical leaks and drips. You say the body is in good shape, make sure you inspect underneath very well and also look at the frame. CJ's can be rust farms! Buying a CJ is no different then buying any other vehicle with two BIG exceptions.
1) You have running gear in the front and the rear so you have twice as much to inspect.
2) That CJ is 45 years old so no matter how good you are at inspecting it, expect to have and find many problems that were not apparent during the inspection. Make sure you set aside coin so you can fix all that will creap up after a purchase. It always does!