Turn signals were not standard equipment until late '50s.
1954 was the first year that factory option/installed turn-signals were available.
As 3B posted, accessory turn signals were available prior to 1954 (GM and other units installed by dealer, by owner, by shop, or by friend/relative).
As 3B posted, the factory wiring diagram did not show signal wiring. The wiring was specific to the accessory unit that was purchased.
