Adrienne,
Smart, McClary and Findlay are old Canadian foundries that were absorbed by GSW (General Steel Wares). My father has a skillet marked GSW in a shield logo. I have seen a Findlay marked pan with this same GSW in a shield logo. Also have seen them without the logo on items that appear older.
I see Smart pans both with and without the Diamond "G". I suspect the "G" was added after the merger, but I can't say for sure.
If you Google "General Steel Wares" in quotes you should find some info on this company.
Chris