Thats a nice thing with WASR's, they have almost no finish on them. Mine had some smiley oil on it. Probably cosmoline.
I used a bit of 100 grit on it, unfortunatly there was an imperfection in my wood that they covered up with just glue that fell off so i made up sawdust (from the gun) and wood glue and it was was fixed right up.
I progressively went up grits until i got to what i wanted.
Applied red mahogany a couple times and then a half dozen or so layers of semi gloss.
Downside: all the wood on my stock was 3 different types of wood so they all accepted the stain differently. One is lighter and one is quite dark, to me it added a little more character because they aren't overly pretty guns to start off with.
I would avoid that Russian red crap. everyone that I've talked to has regretted the fact that they did it and now have a red gun (pun not intended).
Polymer is just a cop out and just seems like a waste on a inexpensive ak. Once you go polymer, you'll want to stick everything and the kitchen sink on the dang thing! Soon enough, you got an AR-15 barbie gun.
I find that wood adds a lot of personality to a gun and gets noticed (and complimented) more than your accessorized AR