First off Marc, I'll remind you and everyone else that there are no stupid questions. Though sometimes you may get an irreverent...er...irrelevant answer here. The Scrimshaw numbering system is a muddy puddle if ever there was one. There was some belated attempt to standardize the system, but still....the catalog may have it one way, the tang may have it another, and the box either way. So the question is, what do we as collectors want to go by? Want the production records? Can it get more official?
1975 Production Report- 260 S.C.
1978 " " - 152 SC
1983 " " - 505SC
1984 " " - 505SC
1985 " " - 505SC
1986 " " - 505SC
1990 " " - 502SC
By the catalogs-
1976 Catalog 152SC
1978 " 155SC
1983 " 502SC
1984 " 502SC
1985 " 502SC
1986 " 502SC
1990 " 502SC
So the catalogs and production reports pretty well agree. But not always with the tang stamps.
Michael