Marcus:  I believe there was a close-up of the 1899 Carbine Action in the pictures you first posted.  It looked to me like there was fine surface pitting.  I think this is also present on the close-ups of the 1901 Carbine rear sight.  These are not deep and not to be messed with.  They give a bit of patina and character.  Because it appears to be a correct carbine and has nice wood, the whole package is attractive.  Because the barrel finish is gone, if this carbine were mine, I would burnish just the barrel with scotch brite pad and fine steel wool.  I'd degrease the barrel surface and apply plum-brown and then several coats of cold-blue over the brown (to just the barrel) gently applying some heat with a propane torch with each coat.  Wipe the barrel with wet rags, dry, and then wipe with oil soaked rags.  I normally only preserve original finish.  But IMHO this carbine would be inhanced with a dull blue finish on the barrel (and it can always be removed).