There are small year to year differences in the cabs but if you stick with 52 year model pieces you should be good.
I've got a 1-1/2 ton cab sitting beside a half ton cab out by the garage and cant find differences in the cabs them selves.
Here is a list that shows most of the changes year to year.
http://www.adchevy.com/info/yeartoyearchanges/
I don't know how accurate it is but it does show the most obvious ones.