Welcome aboard. Former Ft. Lewis Infantryman here. Our unit was moved to Germany and no longer is there. Great place, wild times there. The bike looks to be decent. One thing I have picked up from the members here is the bike is worth what you want to buy it for. If you decide to buy, figure money to clean the carbs, change the oil and to complete the basic 3k tune-up,although if you have any mechanical skills, very easy to learn. Figure you will most likely want a new muffler, thing is fugly but to each their own. Plus this site has the 188 page manual to walk you through step by step for pretty much most maintenance....Figure a new seat. Check the forks, see if the seals are still good. If not 15 bucks on ebay, and the cost of the ATF fluid, 8 bucks......Check the head gasket and make sure to check the casings on the engine out. Take your time when doing this!!!!!!!!!!!!!! Check the chain for any cracks, ask the owner some of its history and while driving see the the rear seems loose. If it does, it may need new swing arm bushings. IMO, 1200 not a bad price but I would think more around 6-800.... Listen to the guys and play with the idle screw... If the bike doesnt idle around 1k it will need a tuneup... Be as picky as you can to lower that price..
GL--Tews