Well, it is the correct bayonet, but tolerances being what they were at the time you will occasionally find one that doesn't fit. I know at least for the export guns they were ordered as a "stand of arms", with all the accoutrements coming individually numbered to the guns and not necessarily interchangeable - not sure if it's the same for the government production examples (and don't have my books handy to look it up)... but if they're purchased separately there's always a chance (not a huge one) it won't fit.