National Postal Meter M1 Carbine .30 Cal Semi-Auto 1943

Up for auction is a WWII .30 caliber carbine made by National Postal Meter in 1943. This gun was inherited by my dad from his cousin who fought in WWII and Korea in the US Army. My dad has taken good care of it and you should be able to see that from my photos. I don't know all the specific terms but will tell you what I have gleaned in my research. The gun is marked with "National Postal Meter 4288980" (*so it was made in 1943). Also it’s marked "US Carbine Cal 30 M I". There is “ IBM Corp” on top of barrel and “Blue Sky Arlington VA” on the side. Other markings-On the sling notch there is “RMC” (for Rock-Ola). On the trigger area-the safety has “J.A.O.” , the button that releases the clip has “M” and on the trigger guard is “J”. There is a “R” on the front sight. Also there is what I call a clamp that is attached to the barrel and forestock that is marked “AI”. 

I am including a old military gun case(I haven’t unzipped it due to it not sliding easily and I don’t want to force it), a unused sling, and magazine clip pouch.