Roffensian wrote:
Even in this example, should we assume that the hands were a service replacement, or is something else going on......
Yes, Roff, you're right--hands are definitely not period correct--probably off a mid-60s version. Likely they are all interchangeable, as the caliber remained consistent and we often see this sort of mismatch.
Also, just for the sake of completeness, here is the outer caseback I really should have posted earlier:

So we have a standard 806 caseback. Maybe the "blanks" were reseved for the Val. 72s only? Or has someone got a documented Venus 178 without the "806," as well?
Roffensian wrote:
Oh for some records!
I empathize but it appears we are never going to get access to definitive records and that they probably don't exist. So, in my experience, it is best for interested collectors to share and amass their own information data sets based on real world observation of genuine models by reference and case serial. These can then be correlated at a later date into a cohesive chronological list/table and certain patterns will reveal themselves. Or at least known variations within a certain production time frame may be able to be observed and/or confirmed.
Best,
T.