It appears to be marked Horse Shoe Brand, St Louis, but was made by Pachmayr. They would make up pads with desired marking at one time, various gun shops had them done. As I remember, Winchester had them make pads for then for a while, marked Winchester.
It is a Skeet model, and probably old as there is no white line, although they recently offered a lot of models without the white line. Never saw a Horse Shoe Brand before.

Dennis Potter