This gun being in 6.5mm makes it a 91.  Having the fixed rear sight and dated 1938 or after means that it is a 38.  Having the fixed bayonet means that it is a Cavalry carbine, Thus we have a M91/38 Moschetto Per Cavalleria or Cavalry carbine.  There is one exception to this rule, Brescia made M91/38's will have an adjustable rear sight which makes it confusing.

Model 91/38 Moschetto Per Cavalleria not dated meaning that it was made in 43 after Musolini was removed. Made only by Gardone with no date or manufacturer stamp

Sling is for the Steyr 1888 Rifle- I like to place slings on my guns from countries where they have been
and the Carcano has been all over the Balkans, where the Steyr was used.

Another M91/38 made in 1940 XVIII by Gardone, late war Carcano or SMG sling

91-38 - 1941 XIX
Brescia did not change the rear sight as the others did keeping the adjustable sight
Late model sling made like the German K98 sling