Mystery collar help

Hi Everyone,
I am hoping for some help identifying the mystery collar that came on the used Cal I got recently. I bought the Cal in Sacramento. It supposedly belonged to a retired CHP officer, but I don’t have any way to verify that.

The collar has all male snaps. There are 3 snaps centered around the middle third of the collar in front. There are three snaps evenly spaced across the back of the collar. The snap pattern does not fit the Cal or my Schott jacket, so I don’t think it is either of those. The snaps are stamped with Rau (or Rao) Fastener Co. Providence RI, so maybe an East Coast maker?

Happy to hear from anyone who has any clues. Also, I am happy to part with this collar to help finance having one made for the Cal with Gwen at Cal Leathers

I am thinking about fiddling with the snaps on this collar to try for a better fit to the jacket. It seems low risk, because I would only mess up the collar, not the jacket. All the snaps would be hidden when the collar is attached. Anyone attempted to do this before?

I have, it's really easy! Is that a GB collar?