even the exact same watch on ebay awhile back. came from a watchmaker in germany. the listing had that it was a modified heuer with a standard eta/valjoux 7750 and decorated, etc and see thru back.

from the listing it was a project watch a watchmaker did with either spare parts and/or parts he could get and made for himself. at some point i guess he sold it. i don't know if this same maker made only one or a bunch? i didn't pay that much attnetion to the listing at the time as it didn't interest me all that much, but what i said above is what i remember. hope that helps the reader a little?

j.h.