Murphy's book does not actually give production numbers of the NST and SM. Murphy's numbers are based on estimates derived from his study of a very small number (170) of guns. Murphy estimates that NST production averaged 100 guns a year, and therefore estimates the total number of NSTs at 3000 to 4000.
Robert Whittington, in his treatise on the New Service, states his numbers are estimates, but his numbers seem to be more detailed, perhaps based on factory research. Whittington breaks his total estimate of 3400 NSTs down by chambering. Whittington estimates there were 1000 NSTs in .45 Colt, 960 in .455 Enfield, 700 in .44 Russian, 500 in .44 Special and 80 in .45 Auto. To me, that means any NST is a rare gun, even in the .45 Colt chambering found most often.
Whittington does the same thing with the estimated 3500 SMs, with 2500 in .38 Special, 500 in .357 Magnum, 250 in .45 Auto, 156 in .45 Colt and 94 in .44 Special. That means to me that the most common SM (.38 Special) is 2.5 times more common than the most common NST (.45 Colt).
Any fan of the New Service needs Murphy's book and Whittingtons treatise. Whittington also has a treatise on the M1909.