Apparently, some of these things were made with serial numbers and the serial number is a manufacturing date code. The folks at the Scubapro museum did some checking around and then advised me:
"Your regulator was produced on the 192nd day of 1995 and it was the 121 regulator in that particular production run."
In another message, they told me that this unit was manufactured after production was moved to Italy. I'd guess that the serial number thing was started after production was moved to Italy.
So, if any of you have a serial number on a Scubapro 1st stage, this might help you make some sense of it.