[78-L] anyone know origin of SA prefix matrix series?

[Thomas Stern]

  Anyone know the origin of, or labels using, a matrix numbers series from a
west coast, Hollywood/LA studio, late 40's, prefixed SA with a 3 digit
or 4 digit number??
  I've seen 6 sides - SA 947, SA 948, SA 953, SA 954, SA 1022, SA 1141.
Thanks!
Best wishes, Thomas.