68 Barracuda complete brake

That's good. If you're really intent on going over everything, then sure take the MC off as well as the wheel cylinders. If they've been working fine, I don't see the need. If its been sitting or unknown, that's different. The bores will tell the story. If there are very minor imperfections, some crocus may take care of it. Any serious rust or pitting, its time to hone or replace as Redfish wrote.

Two other item that are worth a good look over. The hoses and the shoe contact points on the backing plates. The contact points, if worn, can be built back up with steel or brazing.