the car looks in very nice condition but you really need to look at it yourself or have someone you trust and who knows Vettes to look at it in person. you really want to look at the frame and all areas not showing in the pics. i'm also surprised they didn't show the motor which usually means the engine compartment isn't detailed and looking as good as the rest of the car.
The KO wheels are the bolt-on repros. I actually prefer them over the original true KO's but they aren't worth as much.
Personally, I feel that even if the frame and everything checks out OK, their asking price of $79,000 is more in line with a 400hp or 435hp BB motor rather than the 390hp version.
Also, the descrption lists original gauges and from the pics they do look faded enough to be original which also means at some point you will want to pull them out and get them restored or replaced to look good again.