The catch is that Oswald denied bringing curtain rods to work that day and told Buell that he was going to buy his lunch and meantime the 34.8" broken-down Carcano will fit nicely into the 38" bag that was so obviously constructed specifically for said rifle thank you very much.
"...that was so obviously constructed specifically for said rifle.."My analysis of the construction of the bag strongly indicates it is specifically constructed to carry an object 27" or less.
If it was designed for a longer object the seam of the bag would have been reinforced with tape all the way to the open end of the bag.
Obviously, you have no intention of tackling that analysis which would be beneath you as I am still a novice.
Have a little think about why Oswald would have the rifle disassembled - it doesn't really make the package that much more inconspicuous, it will take time to reassemble and, I'm assuming, the accuracy of the rifle is affected by disassembling and reassembling.
There is no upside to having it disassembled in the bag.
If Oswald took the rifle to work with him that morning he didn't take it in CE 142
If he took CE 142 with him that morning, he didn't take the rifle.
Forget a disassembled rifle in a bag designed for something much shorter.
By the same token, it's not impossible.