This was getting no traction on the "Refinishing" forum so I figured maybe here would be better.  I would appreciate some recommendations. I have a new walnut M1A type stock, just in from Fulton Armory. It seems ready to finish, but of course has no metal. I have several GI M14 stocks with all the metal. Would I be better off buying metal for the new one, or would it be not too big of a deal to remove the metal from one of the GI stocks. Also, if anyone can recommend a good course of action for putting a suitable finish on the new stock that doesn't take months of hand rubbing, I would love to hear what's the latest and greatest in that area too. Thanks in advance!

I too, recently acquired an M1A walnut stock from Fulton Armory.

For me, it made more sense to buy the GI hardware kit from Treeline, and leave my factory Springfield Armory stock complete for a possible sale or future build.

Also, I dont know about months of hand rubbing, but I am happy with 2 coats of Tung oil and a few coats of Renaissance Wax.

A military "hand rubbed" finish doesn't necessarily take "months".  Generally, it takes about a week.  Apply a generous amount of finish, rub briskly till your hands get warm.  Let stock sit for about 10 minutes, then wipe off the excess.  Do this about 4 to 6 times and the stock will start to take on a sheen/shine as the pores fill.
Tung oil finish, if pure Tung Oil is used, generally won't change colors.  Raw Linseed Oil(aka Flax Seed Oil) and Boil Linseed Oil will change color.  They darken with age to the reddish brown color of old military stocks.  RLO will darken quicker than BLO.

If you have the correct tools (particularly the handguard clip pliers), it's not a big deal to swap metal. Personally, I'd get all new metal; either way, you're still going to want those damn pliers.

As to finishing the wood, CMP knows a lot about that sort of thing. Their "Armorer's Corner" has a tech article on cleaning and refinishing:
CMP Wood

That aint no joke! Sucks because I knew I wasn't going to need those $18 pliers again... but there I was... ordering my 2nd handguard after I fucked up the first one

This makes a lot of sense and your results are exactly what I'm looking for.  I just now ordered the GI hardware from Treeline.  I've worked with several GI M1 Rifle stocks and a few M14 stocks.  I always had good results, but of course those were all vintage stocks soaked with oil and more or less banged up.  Lots of work.  I've never worked with a new one.  Hopefully it won't be lots of work! Did you need to do much fitting to get it ready to go?

Not much fitting. Fit together nicely.