I don't think you would want to attempt "Restoration" - the gun is in a proper state for a US Arsenal rebuilt "Gas Trap to Gas Port" Conversion of WWII Vintage, and you would be destroying the rifle's true history by changing ANYTHING. Better to find a bare two or three digit reciever and start gathering pieces (Good Luck with That!) than to alter what is here and destroy it's collectability altogether. Still a magnificent M1, just to own, exactly as it is.
Besides that, the parts needed to make it into a real Gas Trap again are pretty much unavailable and might cost more than the starting price of the rifle! A reproduction barrel/gas cylinder Gas Trap setup (making it into a half replica) is $2500, if you can still find one. Nothing is impossible with enough time and money, in theory - but I would leave this one "as found" even if I could afford to buy it. Just one opinion..... CC