Interesting that ten years into the NID era, the Ithaca Gun Co. was using up invoices that still pictures the Flues lock at the top. Looking through some other pics of invoices I have I find this style earlier --
457552 21.jpg
the style with the Flues lock on another invoice from 1938, and then this style in 1942 --
Oct. 17-1942.jpg
That gun would look nice in my gunroom. My NIDs in .410-bore, 28-gauge, 16-gauge and 12-gauge are all 26-inch barrel guns and sticking up right in the middle of that row is my 20-gauge No. 4E with 30-inch barrels.
As to the OPs original question the engraving on the early higher grade Ithacas, prior to the 1915 introduction of the bolder McGraw style, was some of the best.