I stripped and sanded my beech K31, not TOO much, just enought to get out 60% of the dings. Then steamed the rest and refinished with BLO.
"Too far" IMHO is sanding it totally smooth and making it look like a brand new hunting rifle.
That said I just cleaned my walnut K31 and left all the dings. It still looks good, because the walnut is a harder wood, and just doesnt show the dings like beech.
I'm certainly no expert, but unless it is a very valuble rifle (K31's aren't....YET) then a little sanding wont hurt as long as you do it carefully/lightly and use no sandpaper lower than 220. Finish up with 400/600 grit, then steel wool so no sanding scratches show.
NEVER touch a teak or similar stock with sandpaper.
There are about a million threads about this, and surplusrifle.com has some of the best in their forums, way down at the bottom under Gunsmithing, Restoration, Cleaning, & Sporterizing.