Always worth running a brush down the bore. I was going through a lot of "junk" barreled actions not long ago; one looked like it was heavily rusted all the way through, and I mean crusty!
Turned out to be just an even coating of dust and dirt over a like new 1945 5 groove bbl. Another was a M17 with what also looked like a rubbish bore: also turned out to be like new under the dirt.