Dare I say it? Old Ford truck were the same way. I have a 49 ford (forgive me but in my defense I also have have three old chevy trucks) and the key is on the passenger side. The explanation that I have heard is that you were supposed to slide across the bench seat and get out and lock the passenger side. This prevented you from exiting the vehicle on the traffic side. I suppose it also allowed you to unlock and open the passenger door for your gal and let her in like the gentlemen we all are.
Don't know that I believe it but it sounds as good as any story of heard. In the case of the Ford, the truth is probably that they were to cheap to put a lock on both sides. I doubt that Chevys motives were any more admireable.
