Getting back to your original question regarding to STAMPED Stock Copies.
I suspect that you could be right DAVE.
I have seen a Printed DEMO for this one, think it was EAST COAST but not 100% sure.
However, I have two different STAMPED Copies from totally different source to each other.
One has the STAMP on the A Side & the other has the STAMP on the B Side
Surely these were stamped at source, rather than at a later date.
A promotional item not intended for resale at the time. Therefore STAMPED.