It appears to be a multipunched "EPC(o)" pattern. E-96A. This pattern shown on a 1907 issue stamp, would make it the "A" pattern used from 1902-1917. The regular E-96 was used from 1917-1926, by the Eagle Pencil Co., New York, NY. The "non-A" version is a "E" rating (common) and the "A version" is a C rating.
I am not sure if the "A" version has been verified as belongng to the Eagle Pencil Company, but one would venture a guess it probably was (might be in one the catalog update pages).
Here is a scan of both.

The double punching (which looks like what occured) tends to make this a challenge to figure out, but one just has to eliminate lines and dots and "poof" there she is. I would also say that if this is the "A" version, the double punching will lower the sale value tremendously.
Hope this helps.
Now back to postal stationery sorting....
