Take a closer look at the barrel as Inland replacement barrels were not usually dated and just said Inland Div . So I think if you look at it closely under a magnifying glass it should say 8 - 43 rather than 48. The carbine will have been through two rebuild programs. The first will be post WWII before the Korean War when almost all were upgraded and most were converted to M2. In the upgrade, they all got bayonet bands, round bolts, flip safeties, adjustable sights, the new M2 sear, and M2 30 rd mag magazine releases (these have an arm reaching forward on the far right side which corresponds to the *** on the side of original 30 rd mags. All original carbines built during and just after WWII had push safeties originally. Only the really late winchester and Inlands were fitted with bayonet bands originally and the 30 rd mag releases. A lot of the last Inland and Winchester production was devoted to M2 which was developed in late '44 early '45 at the end of the program. Quite a few in the original build got round bolts among them later IBM's, late Inlands, late Rockolas, late Winchesters, late Underwoods and some Saginaws. Round bolts were an effort to make them more reliable and slow down the cyclic rate of fire as well as ease production with fewer machine operations. There would also be a difference in the firing pin in the rebuild program and at least three variations exist. The slide number you mention is a late pattern number and could be found on Saginaw, Inland, Winchester, and IBM that I can remember off the top of my head. Some marked the maker with letters on the outside near the number but most would mark it on the inside of the slide and you may have to remove a lot of powder residue from the piston to see it in the bottom of the flat inside of the slide i.e. PI is Inland SG is Saginaw, IBM for guess who, W for Winchester. Also since that pattern number is identical to the M2 slide except for the side cut, a lot of them were given the M2 relief on the right side by ordinance update shops.
The second rebuild would be when they came back from Korea and Blue Sky which was a Virginia or Maryland Co did reimportation and they went through them again. Also a third build could have occurred to almost any battlefield carbine whose owner was badly wounded or killed. Ordinance companies took battlefield recoverys and recycled them by changing out any damaged parts and putting them back on the line as needed. Weapons that someone bled on or were blast damaged were stripped for parts to replace parts in other damaged weapons and thus have a complete functioning carbine.
I have in my possession a compilation of the first 10 years or so of Carbine Club newsletters and I might be able to give you a more detailed description of how the parts should be marked that should be in it if I had the serial. If you send me a PM with that information, I could look up the serial block and see what the club concensus was on each serial block and you could begin looking for the properly coded parts. During the war years there was a lot of swapping of parts among the contractors to keep up with delivery dates. This also happened among the 1911A1 contractors but not usually to the extent that it did on carbines.
