Conservative,
What George had to say was absatively correct. In stock form, most military arms leave a lot to be desired if you are looking for accuracy. There is a lot of stuff hanging onto the barrel that will effect this, and military weapons weren't exactly machined to exacting spec's either.
If you could find a near mint Swede Bbl, then you could expect a slight improvement in accuracy, but it (the barrel) would have to be installed by a competent 'smith, and then all you have is a new/old Swede. Realistically, I don't think that you could expect any better then 3 MOA with a completely stock setup.
Another thing, the barrels of rifles were rarely marked with the serial #'s. This is because the Bbl has always been considered to be 'consumable' or in other words - a replaceable item. So I don't think that replacing the barrel with a like item would hurt the overall value of the rifle. You Swede collectors feel free to correct me on this.
Personally, since the swede is such a good action, I'd rebarrel with an aftermarket barrel - in the same caliber, and I'd shoot away contentedly!
Good luck,
Unkel Gilbey