Sorry but I would say that is a 67 or 68 SA 200 redface. If it runs and weld good it is worth that but I would offer him 500 less to start. Those redfaces is some of the best 200's ever made. It will have a R-57 vaccum idler hopefully it idles up on it's on. If the owner high idles it by pinning it to get it to weld thats not a big deal. Just make sure it welds good and smooth. Also have him email you the serial number, you can use that to get the exact year.