NRA used to be a techincal haven, so if you can find a gunsmith with a lot of old, old NRA manuals... ()Or a library, ha, ha, ha...) They sold the guns and parts for DCM (Director of Civilian Marksmanship) and info was abundant. Sorry they changed.
Don't forget the gunshows. No telling what some "old man" is giving away. I turned a friend down, offerred to buy, a WW II trigger guard for the A3 (sheet metal stamping I wanted to see if I could make look nicer with bondo) and he gave it to someone else. (Darn) His grandfather shot a 10 shot group at 100 yds, springfield, cast bullets, you could cover with a quarter, not quite a dime... maybe a nickle.
You have a "quest" on your hands. Production stopped around 70 years ago. Many "WW 1's" were reworked for WW II. And they changed the stocks a couple times. I would guess the correct wood would be walnut and the finish, varnish. Repeat "guessing." Luck.