The number is the end of the year.
I have some real problems with the published Fox serial number chronology, which was originally put out in 1976 by Lightner Library.
For 16-gauge Fox-Sterlingworths they are showing production of 500 (1931), 600 (1932), 600 (1933), 700 (1934), 1100 (1935), 1500 (1936), 700 (1937) and then 1600 for 1938. Then the serial numbers from 374800 to 378481 are given for 1939 up to the last gun made 8/9/1939. I don't believe there is any way they all of a sudden pumped out 3681 16-gauge Fox-Sterlingworths in eight or nine months!!! From my 30 or so years of recording serial numbers of observed Sterlingworths, guns in the 375,xxx, 376,xxx, 377,xxx and 378,xxx range certainly exist.
On the 12-gauge Fox-Sterlingworths they estimate the highest serial number for 1937 as 145000, for 1938 as 150000 and for 1939 as 155000. Again from my years of observing and recording serial numbers, I haven't recorded a gun between 143815 and 160076, leading me to believe there were about 16000 serial numbers skipped. Perhaps the high 143xxx range was the end of regular production and the guns in the 160xxx and 161xxx range were cleanup of parts and barrels on hand?!? All of the guns I've recorded in that range are 26-inch barrels except one two-barrel set that also has a pair of 28-inch barrels.
Like the 12-gauges, there is a gap in the observed 20-gauge Sterlingworth serial numbers from guns in the mid-266xxx serial number range, observed specimens jump to the 270xxx range. A gap in serial numbers of about 3500 guns.
Pictures of the production card boxes on racks at Savage confirm these breaks in the serial number range for 12- and 20-gauge Sterlingworths.
