As the last guy in the thread noted, plug the hole with a dowel and re-drill the hole farther back (maybe 1/8”, so you get a snug fit of the barrel and and retainer.
You do have an early single rivet hand guard and an early barrel band and that’s nice to have on an early carbine.
The stock has probably been refinished with Tru-oil and if that’s the case it’s reasonably easy to remediate the shine. Use 0000 steel wool to remove the shine and almost all of the Tru Oil finish. You’ll still have some down in the grain of the wood. Then apply a hand rubbed pure tung oil finish.
Go easy with the steel wool so you don’t round the edges, remove what ever might be left of the cartouches, or start getting waves and ripples in the stock.
If you don’t want to go all in, lightly rub the stock with 0000 steel wool, just enough to knock down the shine to either a satin or an almost flat appearance and then give it a brief rub with a stock rubbing compound.
The top carbine in this picture was an aftermarket replacement with no cartouches that someone probably bought unfinished and then used Tru Oil to finish it. I knocked down the worst of the shine with steel wool. It’s a pot belly M2 style stock and a birch stock, so I replaced it not long after this with a walnut M1 carbine stock rather than take it down to a matte finish or refinish it completely.
The bottom carbine has a stock that was badly stained with more than its share of dings, so it was stripped, cleaned and redone with a tung oil finish.
Since your stock isn’t collectible you have some options, but a tung oil finish like the carbine on the bottom isn’t a bad way to go, and it’s not as incorrect as some folks will tell you.
M1 carbine and M1 Garand stocks were finished by dipping them in tung oil. But that wasn’t where it stopped. Over time the finish evolved with troops rubbing the stocks down with tung oil. A rifle or carbine used by peacetime garrison troops would get frequent hand rubbing with tung oil when ever it was cleaned during the years it was in service.
The end result was not the pristine tung oil dipped finish it had from the factory, nor was it the oil soaked used and abused finish you see on most carbines today. Instead it’s what happened when having a nice looking stock was a point of pride. That practice was very common between the wars and is found on 1903A1 rifles as well. Unfortunately collectors don’t regard it as an “original” finish, even though it was a normal result of military practice for a rifle or carbine that saw years of peacetime service.
You can see the same process occurring on this dip finished stock on a relatively new M1A. The grain is still mostly unfilled but it’s taking on a satin/semi-gloss finish after just a half dozen rub downs with tung oil over the last couple years. Give it several years and a few dozen more rub downs and the grain will be filled as well.
So do what you want with the stock. A finish like the carbine on the bottom isn’t out of place and looks (and is) a lot more original than a new stock, without looking dumpy or abused. Periodic hand rubbed coats of tung oil also fill the grain, seal the wood much better, make the stock much more stable, and increase the durability of the stock.
If you do find an excellent to very good condition original stock from the right manufacturer and cartouches to make it correct for your carbine it will add collector value - assuming your carbine is still mostly original. If you do find such a unicorn, you’ll still want to take your out and shoot it in your current stock so you don’t damage the unicorn.
In my opinion with M1 carbines and Garands over the last 40 years, people get way too focused on the carbine or rifle being “correct”. Quite frankly I regard most “correct” carbines and a Garand with a great deal of suspicion now, as not many M1 Carbines or Garands survived their military service without a full arsenal rebuild. A correct M1 Carbine or Garand today is likely to have several forced matched “correct” parts.