As we've noted several times before, the SAAMI meeting where it was suggested that manufacturers start marking the chamber length on their shotguns was 1937. From my observations, Savage was marking their Fox doubles by late 1938/early 1939. I begin seeing the "For 2 3/4 or shorter shells" marking on Remington pumps and autoloaders on some 1939 vintage guns. Ithaca seems to have been a bit more lax on this. My 1941 vintage No. 4E 16-gauge has no chamber length marking.

[Linked Image from i.imgur.com]

As for the NID Super-10s, their last appearance in Ithaca catalogs and price lists was 1936, before the SAAMI suggestion.