The guy is pretty informative. He has the correct gas tool and has it adjusted for 148gr ammo. He says he thinks it has 6 different positions/ports for different weight bullets.
If it's what you want then go for it... But don't be suprised at the shot groups. Esp. with surplus ammo...
I'd have a hard time trading a M1A, for anything other then a very, very nice rifle, I very much wanted... My M1A was a graduation present from my mother and father.