Yes, two rifles with a full length barrels should have the same length op-rods. Shorter barrel, shorter op-rod.

I have seen one short Italianicon op-rod and it was stamped 7.62 on the handle.

I don't know much about the Italian production of the M1icon so I have no idea if they made M1's with full length barrels in .308 or if they were all shortened .30-'06 barrels.

Why not ask on the CSPicon M1 forum here? Lots of great info there.