FYI all kinds of ex soviet union memorabilia has been sold in the millions post breakup and even before that. You can buy whole uniforms and equipment packs, weapons included for small change. The desperate police / military members sold basically anything they could steal from the government.
I know this doesn't help you but just a warning in case you think it's worth something.
So chances are that badge is worthless.
Well, he is hoping its worth anything, I'm wondering if I should offer him $10 for it or $20, lol.