EXACT compression numbers figure big there, they can have 'compression' and still be junk. I won't buy one myself without a test on the spot. If you are in a hot state then the tensioners will be dying by now too at that mileage, engine work. Valves need to have been chased several times by now and lucky if it has been done twice. If they use ethanol in your fuel the carbs and tank (repaint there) will be messed up too. $100 off right there.
Maybe $1200 MAX if running RIGHT (to 9500 rpm in every gear, RARE, would get you more), no more than $600 as complete as that one is. They cost a bundle to get back right, a real expensive bike to work on. No way do they go for what the earlier SOHCs did. Here in Texas, there are other markets that pay stupid money more. I've bought 900F for $350 before.
Mixed year parts? Side covers and tailpiece say '80 but wheels say '79, '80 wheels were black and the spoke crenulations reversed from convex to concave. '79 will have 150 mph speedo, '80 only 85 mph.