Transfercase access cover

[primal4x4]

I came into a sweet rust, dent free M37 cab and would like to replace the one on the truck. However, the replacement cab does not have the transfer case access hole. Is there cab differences to worry about? Neither is a B1. Thanks in advance.

[RMS]

the differences between the cabs is very small the early trucks have the tcase access, UN power receptacle hole on the dash and the grommets and slots for the first aid kit changed.
there could be more but all the cabs I have mounting holes and the same cowl line