I have not actually looked at it yet. Just wanting some ideas what to look for. I bought my son a R15 in .223 One of the most accurate guns I have seen.
204's arent really known to be barrel burners, even with the velocity. so unless they shot the living daylights out of it...
good news is.. even if the barrel is smoked, you can get a replacement shaw barrel for around $300 or a little under. ar15parts has them in stock in both 20 and 24" lengths.
I had a knowledgeable buddy bore scope my Cooper .204 before a trip for prairie dogs. I had quite a few rounds (1500+) on the barrel. I almost panicked when he showed me pics of the bbl. Looked more like the surface of a rough paved road.
Took it to the range and it shot 1/2" groups at 200 yds. I took it two more trips out west before having to re-barrel it.
Also had my other .204 bite the dust before a trip, but a good copper cleaning straightened it out.
Even if the bbl looks terrible, it still may be a shooter!
Many years ago, I bought a old used Remington 788 22-250. It would only shoot good for about 15 yo 20 shots. After a good barrel cleaning it would shoot good for another 15 to 20 shots.
I re-loaded some V-Max Moly bullets, and they would shoot good for around 40 shots through the same barrel.
Can't help you with the bore but I have a R15 204 22" and love it. I doubt they were doing mag dumps with the 204 so unless they used it shooting a lot of prairie dogs I would think it would be fine. I'm sure a good cleaning might be in store. You'll just have to see how it shoots for starters. Mine will not shoot 40gr bullets and so far I haven't reloaded for it. Mine prefers Remington 32gr Accutips and they work great on coyotes. I only use mine for coyote hunting and bought it new when they came out 10 - 12 years ago and it doesn't get cleaned very often. Also mine will not feed Winchester 34gr hp reliably, it was pushing the bullets back into the case. I use 20 round Brownells aluminum mags. Colt mags will work too, I haven't tried any others.