318 Duster Rebuild - pros and cons of keeping matching numbers

My 71 Duster goes to the shop tomorrow for a fairly extensive restoration. I’ve had this car since new and I know that all major components are still matching numbers. My question is - does it really matter if I keep matching numbers or should I pursue the best solution for the engine, transmission, and steering set-up? I currently plan to have the engine rebuilt - but the shop guy says I might have a better engine if I get a new one.

I’m not trying for more performance - just a car that is much like my original new Duster.

Thoughts?
I'm trying to wrap my head around your shop guy saying it'll be a better engine if you get a new one... There are no "new ones". What you'll get is a different engine that has been rebuilt, just like you want to do to your existing engine. Keep hunting to find a good rebuilder- talk to people at shows and members of local clubs to see who they recommend (or say to avoid!). There are good shops out there- but you may have to wait a bit in line once you find them- but that can also be considered a good sign, since their work is obviously in demand.