Trans vs originality..

Afternoon all,

        I finally have the '59 painted (but not reassembled) and the painter 
is asking if I would like to make a trade with my old smoothcase tranny 
which i won't be using as I am converting to the Datsun 5 speed.  My 
question is should i keep the original trans for originalities sake (In 
case someone else wants to buy my car) or should i just trade it and if 
so, what is a reasonable trade for a smoothcase tranny?

Thanks all!

Lester