As said, there is no OE for trucks, but there is period correct. In 1953 cars, a "Factory optional Accessory" turn signal was available. Made by "Guide". Self cancelling. It was an integral unit blended into the steering wheel. Maybe one of those 1953 car units would work for a truck?...or from a 54 truck as Phil suggested.
The period correct column mount unit of choice for trucks would have been a Guide brand. Owned by GM. Self cancelling. Available at dealers. Accessory shops.
Several other brands were available elsewhere.
The guide unit would be similar to this.
Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn
