I'm the Wiz, and nobody beats me!
The badge dates started in 1976, so a badge without the date was used before 1976. Most likely pulled off a bike and possibly could be NOS or a repop. Hyper-Formance (Pete) had the license to reproduce the badges for Sting Rays so there's probably quite a few hundred/thousand of those floating around. I don't remember if they were the first issue of the small ovals without Chicago, the later with Chicago or maybe even both types. I'd be tempted to get a badge without a stamping and find a die set the correct size and stamp my own before buying one that predates the serial.Frame serial number is FQ511892. I found a badge stamped #1499 on eBay. I'm thinking about ordering it as It's in decent shape, even though it predates the frame stamping.
If there's no stamp on a badge, does that mean it's considered a "spare part" and was not shipped with a bike? Or, are there just a lot of badges out there that were on bikes but never stamped (pre-70s/80s)?