Re: If you're gonna make a fake, get the date right
OK, that looks like the 1905 American bayonet with the hand guard/pommell and muzzle attachment removed.
The blood groove is located correctly and the hilt to blade ratio is correct. It has the "spear point" of the 1905 model. The 1917 model has a "semi-spear" point.
Which, considering we were still using the '03 Springfield at the beginning of the war, could validate the seller's claim. But it's pretty much worthless in its condition unless there is accompanying documentation of its authenticity.