This key likely fits:
Pulled off my Lakin Bob Glaub. It was a custom option.
USA Lakland Joe Osborn / Bob Glaub / 44-60 / 44-64 4 strings.
USA/Korean Lakin Joe Osborn / Shark / Bob Glaub 4 strings.
Likely, Squier Classic Series basses.
All that have a Schaller BM style footprint. Longer stem like classic Fenders.
These are reverse like all classic Lakland / Lakins