Of course you realise that if you drill holes in it to mount sights or a scope, you degrade or destroy any collector value it might have, if in fact, it is in it's original military configuration without modifications. I think myself that I would sporterise a Mosin Nagant before a Carcano, in nice condition. MN's are much more common right now and shoot a much more powerful cartridge. Plenty of inexpensive surplus and European soft point ammo for them right now. And they do make scope mounts for them. Something like a mount that fits in place of the original rear sight and uses a long eye relief scope. An inexpensive surplus Mauser would be even better to sporterise. But I suppose if you take game with the Carcano, it will be something you can boast about as I suspect few ever do.
Your gun is like your nose, it is just wrong for someone else to pick it for you!