See what you mean Rahllo, I can only think maybe a P14/M1917 pommel has been grafted on at some time, haven't got a 14 or 17 bayonet to compare with so its just a guess, it looks like the muzzle ring has been opened up comparing it with the other.

I was thinking early P13 trials bayonet at first, but muzzle ring is too low ( P13/ P14/M1917) muzzle ring is higher.