I actually have a Baikal over/under 20ga. I bought it because the snooty sporting clays guys said they would NEVER stoop so low as to shoot something without a starting price of $10,000. The people that owned them said they were still tight after 20,000 rounds and hit just as many clay pigeons as the $10,000+ guns. Truth be told, the stock doesn't fit me very well. For what I paid, I don't feel bad about reshaping it as a project. It's been on the to-do list for 20 years. What's few more, right?
Anyway, the stock on my shotgun has a matte finish. Not sure if your goal is to make it the way you like or make it as it came out of mother russia. Watco or Tru-Oil (in the picture) will be way better products than anything the Russians used.