I have been reading posts on this site for some time, and now I have a question about a Carcano that I just picked up. It is a carbine that has all of the characteristics of a 91/28 EXCEPT there are no sling swivels on the side AND it is dated 1939. The length, weight and rear sight are correct for the 91/28. I know there are endless variations of Carcanos but I can find nothing on this specific variation. Also, it looks like the rifling is standard, not gain twist, but I am not sure about that. Can anyone help with this?

Thanks,
Bernie