Not all the " short intermediate" actions went to Rigbys.
Im guessing around 50-70ish
The number sequence for this action is a bit odd, mine is in the 100 range....some in their own range, some in the " normal" sequencing.
Early ones had the push button release to the floor plate, but were not hinged.

Heres the really nice thing about mine.....the first 3 numbers of the Rigby serial number are 303!!!!!...what are the odds.

Those of us who are lucky enough to have one, have a very rare Rigby Mauser....enjoy.

Best
Eric