dantforth, been busy on the homefront,but the pictures are quite good and show the pitting.....as I do ALL of my buffing polishing by hand, the barrel is quite easy to do...need to put the action in a well padded vise, and draw file ( fine file) the barrel, small tight rows, then take strips of emery paper.start rough, 120 grit or so, and tear into strips about an inch or so wide the length of the sheet (11 1/2 inches??) and "shoe shine" vigorously around the barrel turn the barrel as you go, the entire length...easier to show and tell and "do it" than try to explain or put in words..........do the "hard part" and a dealer who does 'refinishing' will not charge you as much for this "harder,handwork" you can polish out to what ever degree of final finish you want, keep it satin in the 320 grit range or go "shiney" with 600 and up paper for the final polish...I'd keep it on the 'satin' side for better wear...
as for the 6 holes you show, the two out on the barrel oare the front 'block' (mount) ho;les and the back two are for the 'rear' the two in the middle do not remove or parts will out on the inside ,I recall its for the shell guide or ejector or some such,,,,,been a while..............
send me an e-mail or give me a call some evening and I'll explain MORE if you need...........
I know of a couple of these old carbines that are in "the white" (polished) and the owners just keep them well oiled and they look GOOD..........