Walt's 6 year-old is hyperbole, but he's right. Few bolt action rifle designs have a fixed magazine that projects down from the forestock. Of those, the shape of the Carcano's is unique. You can see the shape of the mag housing clearly in the Alyea film, and there's no question that the rifle seen in the film is a Carcano.
If it's that easy to see what kind of a rifle it was, how did Boone and Weitzman not see it?
They were in the room at arm's length when it was found.
They both hand wrote reports saying it was a Mauser.
Then signed sworn notarized affidavits saying same.
In fact Weitzman signed an affidavit on the 23rd saying it was a Mauser.
The logical conclusion, IMO, if the film is so conclusive of a Carcano being found, is that there was a second rifle found that wasn't recorded on film. Or if it was, that film was ghosted.