Yes, (11) is the country code for Poland. Yours seems to be an issued example or at the very least one that saw use at some point. Value is subjective but I would expect to see a price tag of somewhere near $550 on it if the serial numbers match on all marked parts and the bore was in decent shape. Mint in grease unissued rifles sell for somewhere near $700. If parts are mismatched or the bore is especially worn the price would be lower accordingly.