It's a beautiful classic bike that looks to be in great condition. It's not a rare or highly collectible but if you ride where climbing hills isn't going to be an issue and it fits you well, it's a good starting point for negotiation. I think it would be classified as a "town bike" or commuter bike perhaps.
It appears to have been fully restored, however the original saddle was probably leather and was replaced with a cheaper one.
You said you are looking for a road bike. The AMF is not a road bike, it is more of a townie. But if you want only one speed , fenders and a more of an upright riding position it should work great. Just don't expect to do any 30-40 mile trips with it our race with your buddies.
The price is OK for a completely restored bike, offer him $100 but I would be willing to pay asking if that is what you are looking for.