Being an electric shift 50hp narrows the possible years down considerably. The answer to the question is almost certainly "No". There were some commercial motors made with tillers, but converting one would be a major task and require a parts donor motor.
The Motor is a Mod 50273c (Looks up as 1972)
Ser E06153
Honestly If I could get a tiller to giver me steering and throttle only that would be fine. I have the control box. I could just rig it up in the transom for shift and start.
There really isn't any practical way to set that motor up for tiller steering, because the pan, swivel bracket, etc. were not designed for it. You might want to look at a "stick steer" system, although you may run into a 40hp design limitation on it.