It is a toss up as to whether the Remington Model 1893 single barrel or the Parker Bros. double was the first American 28-gauge.
As to the Ithaca NID, from the NID's introduction in the 1926 Ithaca Gun Co. catalog, through their 1931-32 catalog, the NID was offered in .410-bore, 20, 16-, 12- and 10-gauge. Western Cartridge Co. introduced their Super-X load of 3/4 ounce, put up in their 2 7/8 inch FIELD shell in their March 1, 1931, catalog, and by the first printing of Ithaca's 1932 catalog the NID was being offered in 28-gauge. Ithaca ran this ad in several magazines in the spring of 1932 --
Even though the NID 28-gauge wasn't cataloged, Ithaca apparently did make some in the 1926 to 31 time period.