be it a Winchester, Eddystone or Remington they were all made the same, with the same type of steel, and heat treatment.. other then early Winchesters, parts fit gun to gun, craked 17,s arent as common as the myth says..
id say its more rare then the norm.. though very soft, the 1917 P14 are some of the strongest actions ever,..second to the Type 99 Arisaka, and Smith Corona 1903A3.
id bet lunch your rifle says model OF 1917, and it was polished during sporterizing.
9-18 is likely the original barrel, however...to stir the soup a bit,..the action was likely made well before Sept , and the 2 were mated together after Sept, by Sept Remington was slowing down production of the 1917 and i belive stopped production of new parts in Oct., and assembly of Rifles in Dec..i have the info someplace,,,just have tp dig for it.