I'm not sure how high a quality this would be. My photo is of the inside but the outside is equally dull and blotchy. If, as you say it's post war it looks to me like it might be soon after. When times were very hard and materials most likely scarce.
Being more used to seeing the high quality, pre-war Walther, I find it hard to think that something looking so "second rate" was ever very popular unless there was nothing better available. Perhaps I'll keep it as a curiosity -- I can't imagine that many others are still about!!