watchme
1684
Clavi...see "Reverso...the Living Legend"...
page 266-267. This was a perpetual calendar with retrograde date prototype that was in a Classique-size, of which the one offered this year is the most like.
Frankly, I prefer a solid back for personalization, unless the movement is superbly decorated - of which, being 976-based, I would doubt (good, but not gorgeous).
-Dean