I had a similar thing happen with a guy at a flea market in Dundee, Michigan about 8 years back. He told me my mercury dimes were worth way more than I had them marked and pulled out a greysheet type price list from his back pocket. Thing is, he was only half right, because those prices only hold up if you're selling to a dealer who actually wants them, not some rando at a table. I ended up taking his advice on the key dates and sitting on the rest. Your mileage may vary, but getting a second opinion from a real coin shop beats trusting one guy at a flea market.

Keeping a spare copy is smart honestly, especially for a movie like The Room where everyone wants to touch it and quote it the whole time. Our copy of Troll 2 got so greasy from pizza hands that it stopped working. Now we just put the disc in and nobody's allowed near it.