Usually on the old tin toys there will be a makers mark in the rear window.. like a T.N. (Nomura) in a diamond or a Y in a flower leaf (yonezawa) or something similar.
If you do find such a mark, here is a useful ID guide:
http://www.robot1968.com/logo.htm
If you do find such a mark, here is a useful ID guide:
http://www.robot1968.com/logo.htm
