There are a great number of variations in carbines- maker, flat bolt/ round bolt, hi wood/ low wood, bayonet lug or not, etc ad infinitum.
However, your GI carbine should be worth around $700 or more, emphasis on more. Most that I see for sale today, plain vanilla GI carbine- are around $850 or so. Wish I had bought a truckload of them in 1966 when they were $42 each at the local A&N store.
And where ARE my manners? Welcome to the forum- when you get a free minute drop by the Introductions thread and say howdy.