You get all sorts wood on stocks, some of it mismatched. I had to laugh at the pallet wood reference..Thanks for that.
I bought a yugo sks a while back. The lower stock looks like beech (Im not a wood expert). The upper guard over the barrel is mis matched and a much harder wood. Its striped (light and dark) and harder than hades when I refinsihed it. Definitely a different wood.
There was an old story going round they made some SKS in teak stocks to wiithstand jungle climate and sold them out for an African contract. Who knows?
They both have both been lovingly redone with a BLO finish, as the lower stock was in bad shape and looked like it had black dirt ground into it.