http://www.wiperman.com/His dad advertised Trico Wiper service in Hemmings Motor News since 1970. The son still runs the business.
He could not rebuild my son's 1946 2 ton's wiper motor though he was able to find me a unit that would fit and work.
He should be able to give you the motor number you want. Might get lucky and he can fix yours. Or at least find you one that you could fit in your truck. Jeffrey