Another K31. Is it walnut?

[Daan Kemp]

Urdorf = old town/old part of town. Schönheimstrasse 3 must be in the old part of whichever town it is.
Possible a search for that street name in Switzerland could turn op the town it belongs to.
Or a search for that last name might lead to the street too.

[Aragorn243]

Stock and handguard are serial numbered in the barrel groove. Odd that the date isn't stamped on the butt. If the stock matches the rifle, I wouldn't worry about it. They either found a walnut stock at time of production or it was replaced at some point.

[Dobby]

Lot of incorrect info here:
Fritz Sahli, born in 1934
Schwere Füsilierkompanie IV/68 (heavy infantry=fire support, 4th company, 68th batallion)
Urdorf, Schönheimstrasse 3 (Urdorf is the name of a municipality near Zurich, nothing to do with an old part of town)