How easy and much you spend on your restoration depends on where you live, Mike.
If you live in or near a major industrial center, there will be metal refinishing shops equipped to do your work (blasting and black-oxiding). Look in the Yellow Pages for "industrial metal finishing" or "plating" It's relatively simple to do it yourself and get excellent results. It should cost o more than $30 or $40 + cost of a new stock.
1. Browse the Shotgun News of the Gun List for surplus M1 Carbine stock sources. Lots of them available. A litle stock oil and rubbing, and you are all set.
2. If you disassemble your carbine and have the pieces bead blasted (NOT sand blasted), and then black oxide coated, you will get an authentic and great-looking dark blue-black finish. If you want re-parkerizing, the same shop should know who does that in your area.
Since all the WWII M1 Carbines and their components were made by various contractors and suppliers, it is rare to find a complete carbine that has "matching finish" on all of it's parts.
Unless your M1 Carbine is an exceptionally rare or valuable variant, replacing the stock and refinishing the metal as described will not hurt it's shooting or having value.
HTH
John