I’ve never seen an 870 that needed work, including a couple at the skeet range that routinely get 5-6000 rounds a year through them. Ain't that sweet? FWIW, I knew a gent who owned (owns?) a shooting emporium in Camarillo, Kalifornia, years ago, and he told me about a lady who brought in her Ruger .22 self-loading pistol, because it wasn't working quite right anymore. Turned out it had 10-20K rounds through it (GOOD FOR HER!!!). Ruger completely rebuilt that pistola for her, free of charge (good for you, Ruger!)...
I once traded for an old Ruger .22 Mark I target which was in bad shape, pretty badly rusted and dirty as all get out. I sent it to Ruger and it came back looking like new, and even in a new box. The only way I could tell it wasn't new was they had to buff a certain place so much to get rid of the rust that it had a small depression for an inch or so.
It wasn't free tho, they charged $25 which was still a bargain.