Let him sweat a bit more, then see if he'll negotiate down some more. In the end, it's a pretty fine looking watch, and as John said, perhaps in a few years time, it will seem cheap. Like land, they're not making more of them (well, they are in some countries... but that's a different story).
By the way, that background looks familiar from the Bay... doesn't this guy chuck some lesser specimens on there from time to time? I seem to recall having a good look at a UG Polerouter or similar that some vendor using the same map paper background there a few months ago.