Actually, Murf, a stamp is an excellent idea that hadn't occurred to me!
I think I'll start cleanup and disassembly of the horns.
I'm curious, though. For those that don't have suitable cores, or don't want to spend the time and effort rebuilding the horns, could someone buy the reproduction horns (you know, the ones with the screws), and then remove the screws and replace them with the rivets from Zip Products, then stamp a date code in one of the horns, and wind up with a Concours correct replacement? Or do the reproductions still differ slightly from the originals?