Welcome to the Forum.

The C330XXX serial number would indicate you have a .38 Military & Police from 1955 - 1956. The numbers in the yoke cutout of the frame that you listed are internal factory numbers and are not significant once it left the factory.

You didn't mention the barrel length but these M&Ps came in 2", 4", 5" and 6" with 4" being the most common. In 1957 model numbers were assigned and the M&P became the Model 10.

Russ