On page 166 of Levine's Guide #4, there is a partial list of Schrade Scrimshaws. It only goes through 1996, when that edition was published, and as LT once said, it would be a daunting task to unearth all of the models and variants... (I think it was LT...if not, I apologize in advance and will take my beating for misquoting someone).
This list does not show prefixes or suffixes, just pattern numbers, with a 296 trapper being the only non 500 series. But as Codger said there are other non 500 scrimshawed patterns. "Before and After", as it were, seems to be inconsistent but correct as far as the SC identifier. I just picked up a 505 scrim (with no scrim) and the SC is a suffix.
Just trying to add a bit here.
Bill