What gets worn out on a barrel is the throat area, and not the rifling....that is the area just ahead of the chamber as it turns into rifling. In a non-chrome lined barrel, every 1000 rounds wears the throat about .001...so 5000 rounds erodes .005....etc. (This is a general concept, and mileage will vary.) As the throat erodes, accuracy will deteriorate.
Throat erosion is hard to see with the naked eye...I can't at least, but it is very easy to measure... but only with the proper tools. So basically, what we end up with is that shooting it is the only really practical way to determine if the barrel will give you the accuracy that you desire. It all depends on what level of accuracy you want/need. If you think it shoots okay for what you want to do with it...then it does...end of story.
Also, I have also seen a lot of barrels that were said by their owners to be "shot out". After a good cleaning with the proper copper solvent they looked like new again! With the copper fouling gone...they shot just like a new barrel too...so you may be on the right track here.
Let us know how it turns out.
TC