Look no further than the auction sale post just ahead of your post, sold last September. If I recall correctly this one was located outside Poland. There was also the ‘fake’ one discussed in another thread here (refinished original shell) that sold several days back for about $900.
As you know, auctions are difficult to predict, especially for the rarer items, but it’s a safe bet that a god original example with better than 80% salamandra and original liner and chin strap is likely to see $900 on the lower end.
Question for you: do you know the approximate current market value for a wz.31/50 in perfect unissued condition with the post war pattern liner?