Many gun stores (especially more traditional stores) price used guns at acquisition cost plus a standard profit. That was an outstanding buy, which means that the store probably acquired it for $200 to $250 max.
Finding the wedding ring makes me wonder if a vindictive spouse sold her husband or ex-husband's gun - possibly tucking the ring in there as extra "punishment"... That or perhaps an anti-gun spouse lost a husband to Covid-19 and was uncomfortable about having a gun in the house.
In any case, if the ring isn't claimed, I hope you get it back.
When you buy used "stuff" sometimes it comes with a story.
I like to buy used state police cruisers. They are great cars, and my state equips them with a lot of upgraded features. For years, they were Ford Crown Victoria sedans.
One day, while cleaning the interior of one I'd had for about 3 years, I pushed the upholstery crease at the base of the passenger front seat and low and behold a gold class ring fell out.
Being a class ring, it listed the high school the student attended, year of graduation, and there was an initial and last name engraved inside.
I contacted the state police office in that district, and the city police department and asked them to locate the person, contact them and let them have my contact information without disclosing what was found.
They called me about a week later, described the ring and then told me how it was lost.
Their home had been broken into, and the likely burglar quickly caught and arrested. Apparently, he still had the ring and, while riding in the back of my car on the way to jail, had taken it off his finger and tucked it in the seat groove. It rested there for over 5 years until I was deep cleaning the interior.
The owners had missed and reported the ring stolen in the burglary, and were quite happy to get it back... They own a restaurant and even invited me in for a meal...