Cleaning and refinishing stocks is two different animals. For cleaning, denatured alcohol works pretty well. The Boyds stocks that SA Inc uses generally are pretty dry and could use a judicious application of oil to complete their finish.
The original arsenal finish was a dip in a vat of pure tung oil (PTO). BLO was used by the troops because its cheap and it keeps the troops busy. Tung oil provides marginally more protection from water and scratches then BLO, but still isn't great compared to synthetics. Marine spar polyeurathene provides the best protection, but leaves a shiny plasticky finish that many purists don't like. This may be the type of finish you were referring to? Minwax Tung Oil finish, if you follow the directions on the can, will give you a finish that looks like a BlO or PTO, but provides more protection.
I started off using PTO on my M1A, but switched to Minwax Tung Oil finish after about a year of using PTO.
I won the M1 in a raffle, and it came with a polyeurathene finish, which is shame 'caue its the original stock on a nearly all original IHC. I took most of the shine out of it using Scothbrite pads.