Any time I see a blued frame, it sets off alarms that the barrels may have been hot blued.
In the early days there was a herd of entry-level Ithaca doubles, all with the company logo and dog roll-stamped on the sides of the frame and a capped pistol grip -- No. 1 had Twist barrels, the No. 1 Special had Cockerill Steel barrels and the No. 1 1/2 had Damascus barrels. Then they added an even lower priced Field Grade with smokeless powder steel barrels and a half-pistol grip stock. During 1915 as Ithaca went from their early style fine engraving to the bold (cheaper to produced) McGraw style engraving the No. 1 1/2 got the bold floral engraving and the option of Krupp Steel barrels.
Ithaca Flues No. 1 and one half, July 1915.jpg
Over the next five years, as the war in Europe cut off the supply of composite iron and steel tubes, every Ithaca Gun Co. catalog shows differences in these entry-level doubles. Once the No. 1 got steel barrels the No. 1 Special was redundant and was dropped. June 5, 1918, catalog --
No. 1, June 5, 1918, Pocket Catalog.jpeg
No. 1 1-2, June 5, 1918, Pocket Catalog.jpeg
Then by 1919 the No. 1 and No. 1 1/2 were combined as the new No. 1 --
No. 1, 1919-1920 Pocket Catalog.jpeg
with the bold floral engraving.