That is a very nicelooking No. 2 Flues Model Ithaca.
Ithaca changed to the bolder Art Nouveau style engraving in mid-1915.
By 1919 this style engraving became the No. 1, and remained the No. 1 through the 1934 Ithca catalogues.
From the 1925 Ithaca catalogue --
And, here is the pattern on a Magnum-framed NID --
Bill McGraw was still pretty young when the new style engraving patterns were introduced, but this style engraving has certainly become associated with him. I've always thought that this later Ithaca engraving has bit of a Rudolf Kornbrath look about it.