Sorry John, but David Josephs has proved conclusively, definitively with photographic evidence that the rifle that Lt. Day carried out of the TSBD has none of the markings on the rifle that was later entered into evidence (CE 139):
The Mauser, the Carcano, and the Lt. Day Rifle
https://www.kennedysandking.com/john-f-kennedy-articles/the-mauser-the-carcano-and-the-lt-day-rifle

You remember Josephs, right? He used to share his wisdom with us here on this forum. Since he left, we are no longer treated with such insights as the following:
There is no evidence Kleins ever had C2766 to ship in March in the first place other than a list of 100 rifles for which not a single other rifle has EVER been found - only C2766. - David Josephs
The Stub, from which the PMO[Klein's money order] is discovered and at one time was attached - is the very thing that gives the PMO any initial credibility. To then claim not to have this item breaks the chain of evidence. The PMO then requires other forms of authentication. When that cannot occur due to conflicting evidence, that item cannot be authenticated or regarded as "real evidence". It's worthless. - David Josephs
The home address in Alexandria, Virginia of Robert H. Jackson, the purported finder of the PMO at the National Archives and Records Service, Federal Records Center "does not exist", and thus it's unlikely that Jackson ever existed.-- Paraphrasing David Josephs.
Hey Tim, yeah I remember debating Josephs and after he had endless troubles defending his "ideas", he went for greener pastures where as long as you toe the line, everyone kisses each others ass!
And your examples made me laugh, it's reminds me of DiEugenio who claims that because no one at the post office remembers an 8 month old transaction then obviously Oswald never received the rifle! You can't make this $hit up!
I had a look at Josephs "The Mauser, the Carcano, and the Lt. Day Rifle" PDF and wow what a load of garbage.
1. Josephs alludes to the fact that because a 7.65 Mauser was "identified" that the rifle taken from the Depository was a Mauser but the photographic evidence is solid that the rifle was identical to Oswald's Carcano.

1a. A 7.65 Mauser while similar is different when directly compared and understandably in the darkness of the 6th floor a misidentification is excusable and I wasn't there but I doubt that the murder weapon was handed to each officer so they could closely examine it.

2. Josephs comparisons rely on images which have been heavily processed, for instance the following comparison comes from the primary source that Josephs links to and his extremely contrasted inverted misrepresentation is clear to see. The official image from the WC in extreme closeup can be barely seen and the 6.5 is not even visible hence Josephs compositing a 6.5 from another source and even with this overlay the 6 is virtually invisible. Also worth considering that there is probably some fingerprint dust on the rifle which would further obscure any detail.

JohnM