The thing that stuck out right away was that the "U.S." was not centered.
Oddly, that is the second "1903" with fake markings to have shown up on these sites. I don't know who is turning them out. We usually see that kind of thing on dummy guns made for collectors, mainly Japanese, who are not allowed to own real guns, but have the money to spend on reasonably accurate "non-guns."
From time to time, some of those are sold on the net as genuine or with descriptions worded in such a way that the buyer can be deceived.