Hi Vince - Glass bedding an M1A should noticeably increase the accuracy of any rifle. This can be a tricky process for the inexperienced (like myself) so I recommend that you purchase a surplus M1A/M-14 stock (many sources out there) and practice on that one. Get a stock that you will be willing to use for a while, as once the rifle is bedded, you should really leave it assembled until rebedding is necessary. My last bedding job lasted 10,000 rounds and probably could have gone longer but I had the itch to do it again.
With the Springfield Armory M1A (and most other M-14 clones), G.I. parts from the origianl M-14s will fit and function perfectly if your rifle was made to military specifications. If G.I. parts won't fit and function, your rifle is out of spec. I would highly recommend that you at lease replace the bolt and operating rod of your new Springfield right away, as these are the most critical components and should not be entrusted to cast pieces. Don't worry though, the cast parts should hold up fine for a while and you are in no danger!!!
Good luck!