That sucks. I don't know how it works today, or even 20 years ago, but when you threw a 300 the city association officers would be called and they would verify the lanes. By verify I mean, check them to see if they were legal as far as the oil pattern goes. If they give the game their blessing the info would be sent to the ABC (American Bowling Congress) and they would issue a prize to the bowler who shot the 300.
That's how it worked years ago. I'm not sure the ABC is even still the sanctioning body today. Since you guys weren't in the league at the time of the score, he probably got credit for the record, but no prize from the ABC. Only guessing, been out of it for a long time.
Back in the 70s and 80s when 300's weren't shot as often as they are now, you would get a prize of your choice. Many took a ring. It was gold with a diamond set in a ruby. It had your name and date inside the band. They were worth a decent amount of money at one time. I know a guy who had one appraised at over $700 bucks. This would have been back in the early 80s. Since then, and because it is so much easier today, they only give out much lesser prizes. Maybe just a patch.
Funny, I just read a while ago: A 10 year old kid shot 244-248-276 for the huge 768 series today in the USBC Youth Scratch Tournament. That's nuts! Nothing against the kid, he's probably really really good. But it seems awfully easy.