The Signet was the top-end package. Canadian built cars up to 66 (fact check please) were "Valiants" not Plymouths and would have the Signet badging instead of GT in the case of Dodges. My 64 would not have had Plymouth anywhere on it but would have Valiant hood badge and Signet trunk badging. Steering wheel logo was the same though.
@hotrod swinger was I close?