If it was made at the school, it will have a number either below the end pin, stamped into the wood, or earlier instruments has the number inside, on the back, near a lower corner block, as the instruments from the Mittenwald school did and do. Peter said that they went to stamping the lower block because of cracks.
Peter put the Prier Inc label in things that he sold. He told us that was because if someone wanted to trade up, how do you know that you sold them the instrument? The label.
If it has the number, sometimes the folks at the shop will be kind and tell you who made it.
I have a 3/4 that is out on trial that was made at the school, so if it comes back in, I will take a picture of the number.
From that time frame, it would be a 3 digit number. I was there when instrument 1000 was stamped.