When you say between '50 and '54 just what do you mean?
A '50 has turn-down type door handles, no wing windows, and a split windshield. The top edge of the bed is angled.
A '51 is just like a '50, except it has wing windows.
'52 and '53 have push button door handles.
'54 has a different grill, curved glass windshield and a flat top bed.
You might want to spend some time browsing the gallary here to understand the differences and decide which if any matter to you. I've only described the external differences, there are mechanical differences also.
