Check the result of the last auction at watchesofknightbridges, lots 268 - 278. http://watchesofknightsbridge.com/view-auction-catalogues.html A couple of Speedmaster were not sold, even 105.003, 105.012 and 145.012. Maybe the reserve was set to high? The watches were not perfect, but not that bad either.
Have a look at the Speedmaster 101 blog for a more in depth analysis of the sale. I think you will find an excellent starting point to consider.
Thx Joe Being honest, I did not analyze the condition of the watches that accurate. So instead of a noticeable drop in prices it's more like Speedmaster 101 is stating at his price chart "Over prepared, or poorly prepared watches are not selling."
I just had a look at Speedmaster101's post auction assessment, and I can hardly say I'm surprised they didn't sell, just a bunch of ugly watches. I personally would much rather have a later reference in great condition instead of one of these ratty, dog eared looking earlier examples.