What you are looking at is a VERY high quality kit gun built on a Coonan type 1 reciever. In order to be compliant with the law, there must be a number of components replaced with US parts. This one has the receiver, hammer, trigger and sear (FSE type M3 which is the best there is), and I think he installed a Tapco charging handle and put on a US pistol grip.
The finish is done with Gunkote, which is a VERY hard and durable finish. It looks good too. I've personally shot this rifle and I can tell you it runs like a top. I can also verify that it headspaces correctly. I know this because I helped barrel it.
Buying a home-built FAL can be scary, which is why he is only asking $650. People view it as a gamble because there are some poorly built and non-compliant ones floating around. I can promise you that whomever buys this one is getting a bargain.