By comparing markings and workmanship to a known original (and to known reproductions). A certain sign of a modern reproduction is the marking "Black Powder Only"- since at the time the originals were made, there was ONLY black powder.
Varies according to when made.
There is a .50 replacement barrel on Gunbroker.com
Take it to a gunsmith. That is what they do.
50-159 USD
100-400
You must call TC
50-500 usd
No. 10mm is close to .40 cal, smaller than .50 cal.
50
Depends on the load
You can put a scope on a CVA .50 cal. Missouri.
the 50 cal has 10 and the intervention has 5