Last week, on a 110 yo. LC Smith ten guage, I cleaned the stock with full strength Murphys Oil soap...rinsed quickly with water which didn't hurt anything, but the finish was uneven and mostly gone. The gun was not collector grade, just a sentimental family heirloom. Finish came off well with Zinsser Strip Fast Power Strip spray...Murphy's followed that again.
Park's Furniture Refinisher was then used, containing acetone, ethyl alcohol, methyl alcohol and tolulol....made a slurry in a small glass jar to about the consistency of pancake batter. The dry component is "whiting", powdered calcium carbonate which is chalk. Whiting is hard to find but available through Amazon. I got mine from a stained glass shop.
Warm the wood before applying with heat gun or oven. This is for bringing out the gun oil. Set it a warm place after, and the white powder will turn brown as the gun oil comes up to the surface. Repeat again in the remaining darker areas until the overall color looks even.
The boiled linseed oil finish will be gone by then so remove the dents with wet t-shirt and a medium heat dry clothes iron, leave the gouges for historical reasons and attempt a refinish and sheen appropriate to the gun and period.