Just to be exact about the information in Pate's book: I hope I won't get into trouble for an extended quote, but if I am out of line, let me know.
"One thousand .38 Special M&P revolvers were shipped to the U.S. Marine Corps .... Philadelphia PA in 1932. ... this discovery by Roy Jinks, factory historian. ... Serial numbers ranging to 624524 were shipped on Sept. 10 ... Others were noted as shipped on March 3, 1932 including 624509, -18, -20, -27, -33, -37, -50, -55, - 56, -62, -65, -72, -79, -88, -609, -14, -15, -631."
...
"Others were scattered over several thousand numbers. Sixty were in the range 627375-627975 ... shipped March 3.... 100 additional revolvers were shipped on Sept 10. ... blue finish, 6" barrel, square butt...cost was $19.57 each."
The scattered shipping indicates to me that the guns were not being pulled out of storage or even assembled from stocked frames, but were actually being made at that time.
Anyway, that is what I have and credit goes to Charles Pate, whose book I heartily and highly recommend.
Jim