91 doors on a 73 cab????

[kanuck]

Was wondering if anyone could tell me what issues I may have with a set of doors off of a 1991 GMC Jimmy when I install them on a 1973 cab.

I am getting ready for paint and found out the doors on the cab are aftermarket replacements and will take to much work to get nice and straight, and are still not that great quality. Metal seems fairly thin.
I have a beautiful set of original 1991 Jimmy door that just need a sanding and should be ready to go.
I know there is a difference in the door panels, but will I run into any problems and do I have to do any changes or prep to make them work/fit?

Thanks for any advice you can give.