Also should mention that I did not scale the pictures specifically, it was just visual reference/comparison for the grips
I have a production cast of the miniseries pistol (also used throughout season 1 on Caprica), the casts are well made, the revolver inside is cast separately, I'll check tomorrow, I think there are still some markings on it.
Another potential monkey in the wrench is that they also could have used a Taurus revolver as those were very close to the S&W revolvers in terms of overall shape due to the ties between the two companies. Not that Taurus made knock offs, but they were damned close.