Barbie ne Chambers removed the barrel from a customer's rife, one which had been cleaned without every being taken apart since new. The bottom (hidden) flats were a mass of rust and pits. Go
figure!
Due to the generally better condition, as Mikey says (I've noticed it as well) of original guns in-stock barrel parts, I surmise they were taken apart and cleaned and perhaps oiled, more often than
one might think.
As these old guns were constantly out in the weather, hunting etc., barrel removal for cleaning and oiling simply makes sense on a tool designed not only to feed you & your family, but also to
protect you and your family's lives.