I doubt if your stock is from a No. 3 as the wood on them was usually quite nice. Catalogs listed No.3's as having fine European Walnut.
I have a photograph of the dock at Hunter Arms showing a mountain of walnut waiting to be put away and dried. I doubt they would run out of wood for a lower graded gun, BUT this does not mean that it could have not be ordered that way, but I doubt it.
In the year 1912 is when the grades were changed from a number to a noun, except for the Monogram and Pigeon.