I have one of those SC501's too. It is a 154OT Droppoint hunter pattern. The blade on mine is carbon steel. I think the plain shield and the rivets are nickle silver. Maybe someone can tell us how they came to be produced.
SC prefix or suffix generally means "Scrimshaw", I think. I have seen a deer head scrim on white delrin with the SC501 tangstamp. Maybe they were overruns on production that were sold as seconds.
The Droppoint hunter pattern is a handy field knife. I dressed a deer with mine this fall just to try it out. The choil, like it's brothers the 152OT Sharpfinger and 158OT Guthook Skinner, forms a lower guard that keeps your finger from slipping onto the blade. Handy feature in a short handled knife.
They were made under the 154OT tangstamp from 1976 - 1998 if my info is correct. I have a Skoal edition 154G with green sawcut delrin scales and an oval brass Schrade shield. Same pattern though.
Codger