The rem Model 14 pump was mfg'd from 1912-1935. A "carbine will have an 18.5inch bbl, a full size rifle will have a 22" tube. Beware that true carbines are a bit scarce and lopping off a barrel to fake a carbine is not uncommon. If you have a true carbine it is desireable. They were chambered in a family of Rem cartridges to include .25, .30, .32 and .35 Rem. They were in direct competition with the assorted Winchester lever cartridges and rifles. If I recall correctly the Model 14 was a Pedereson design. The "candy cane" spiral magazine tube was intended to off set cartridge noses and primers in the tubular magazine to allow the use of pointed spitzer slugs, and provide an advantage over the tube fed Winchester levers. Thing is, I don't think there were ever any factory spitzer loadings. NOte that .32 Rem is no longer in factory production. Maybe some shop like the Old Western Scrounger carries it, or some other boutique outfit, but you will not buy a box at Wally World.
Drilling and tapping the receiver of a Rem 14 to accepet a base and rings for scoping will adversely effect its value. Especially if your gun is indeed a factory carbine. Many were drilled and tapped as scopes became acceptable, , as I've seen many scoped, so one that is not drilled is desireable from a collector stand point.
Regards accuracy improvement, there were model specific peep sights, receiver mounted, very slick, that increased the sight radius and typically accuracy. I saw a MOdel 14 over the Thanksgiving weekend that appeard to be factory drilled to accept a receiver mounted peep. My own model 14 is NOT so drilled.
A period vintage peep like an old Marbles installed on a FACTORY drilled rifle (again if there is such a thing) would not hurt its value and might improve it). I would not drill one to take a peep.
The MOdel 14 were succeeded by the Model 141. That line of old school Rem pumps are near and dear to me, and were a family staple growing up. They are light and sleek and what a woods rifle was meant to be. To buld one today, with all the machining and fitting, would cost a fortune.