Is there a cartouche on the stock? The stock could be a "schools rifle" original from the look of the work. The barrel however is definitely an after the fact modification. An actual 22" turned down barrel is finished and crowned much much nicer. The extra length will preclude bayonet lock up as you stated. Correct length barrel necessitates removing the front sight blade in order to get the forward barrel band off, it appears the forward barrel band could be completely removed from the stock without doing that on yours. Still a nice looking rifle be fun to shoot.