Wow, Great thread...
I've never seen them stamped on the bracket, Always inside the horn on the lip of the large air inlet. I just re-did my horns last month... Re-stamping it would be nice... My old stamps were so faded, I could barely make them out.. May 18th '66 Dearborn build Sprint 200.
Jeff is right though, The original fonts were obscure, definately not run of the mill fonts...Would still like to see someone take a stab at making the stamps though. I've had numbers of great stamps made at Office Depot. I'd have to work a long time in order to make these. Usually, I have something printed to work with.. Not the case here..
Tony K.