IES Penn State Engineer Key Charm Pendant Vintage University 1940 For Sale

Neat pendant charm found at a PA estate sale. I believe this is an engineering charm. It reads \"E.A. Zacks 40\" on the back which I think is probably the owner and his grad date. There is one other imprint that I cannot read. I do not believe that it is a precious metal stamp as there is patina and plating loss of the old overlay. See photos.