If i'm not mistaken thats an M1 Garand you got sittin there. My dad has one. Is your's from the war or is it a remake? Apparently the ones from the 1940's have a waiting list and there is no guarantee what kind of shape they're in or if they even fire, so my dad shelled out the $1000 for a new one. He loves it.
Each company, due to their individual manufacturing abilities produced different amounts of M1's. Springfield Armory produced the most -- several million, Winchester came in second, H&R third and International Harvester pulled up the rear. Thus, Springfields are easier to find (and cheaper) than say an IHC.
There were different styles of M1's as well. The real early M1's had a unique gas cylinder, called a "gas trap". These are very hard to find and command a premium for collectors. There were also different sights. Ones with "lockbar" sights, are also relatively rare and thus expensive.
I guess i should stop the lecture. I could go on for days and bore everyone to death with arcane facts and figures.
Anyway, mine's an all-correct (all if the individual parts are the original ones) International Harvester, manufactured in 1953.
Tell your dad about the CMP (Civilian Marksmanship Program), which is a Government Run outfit that sells Government surplus rifles (older ones such as the Garand, M1 Carbine, etc.) for very affordable prices. They have been selling off gov surp for decades now and are starting to finally dry up so he should hurry. http://www.odcmp.com/