There were 887 Ithaca NID Magnum-10s produced but scattered in among those were 87 Magnum-12s, so I'm not a good enough math guy to figure the odds of consecutive numbers showing up.
July 1932, National Sportsman, Magnum 10.jpeg
Allegedly there were only five hundred and some NID Super-10s produced.
Super 10 Ad, American Rifleman September 1929.jpg
1936 was the last year the Super-10 was carried in the Ithaca Gun Co. catalogs. The Magnum 12s first appeared in the 1937 Ithaca Gun Co. catalogs. However, I've recorded Magnum 12s as low as 500144 so either they were making them earlier or the magnum frames were getting used way out of order.
Threaded Mode