Anybody out there know much about these guns? I have one that looks to be in good shape but the thing I'm not sure about is the barrel. It is marked "Underwood 2-46" with a logo beneath the letters that looks like a circle with a wing on top.

Underwood is listed in the Blue Book as a manufacturer of M-1's as well. The safety has the letters IP-W on one side.

Any help would be greatly appreciated.

The stamping with the circle and wings is the ordnance symbol, bomb, and no these folks did not mfg. the M1 Garand.
Mfg.'s of the Garand were Winchester, Springfield Gov't Arsenal, and when Korea kicked in and shortly thereafter, early 60's, International Harvester and H&R also mfg. the weapon. Check out www.odcmp.com for pretty good history and details on the Garand.
Mfg.'s of the M1Carbine were many and varied and value of late has crept up quite high. If yours is all original, even better. Perhaps others here can give you details of your carbine with more data from you.