Me, I'd be looking for a lot of photos of a watch that's about to cost me thousands of dollars -- not only because I want to look and see if anything POPS at me in a bad way but also because I would be excited as shit and want to see as many photos as possible, well, because!
When I've purchased privately I usually receive around 10-15 photos... maybe six of those the seller has already taken for their ad while the rest are at my request.
Clearly the watch is authentic, as already established, at this point I'd be wanting photos for excitement and condition wear & tear documentation.