Im all new to the Mopar family, I and son attempting to restore 1968 coronet. We like the rallye gages better than the standard that are in the car. My question is, can I interchange these in the dash and will the wiring harnesses work?

Also needing front fenders, in classic industries catalog they sell a 1968 b-body Plymouth front fenders, will these fit correctly on my 1968 coronet?
Thank you