Put them on ebay at $0.99 and you’ll find out in 7 days.
If there aren’t many around then there aren’t many changing hands, so you can’t easily put a price on them.
I figure roughly about what a pair of used B125AAs is worth plus a slight curiosity premium, depending on the condition (scratched, stickers present, etc). More if you can convince a few hipsters to bid against each other, but they’re not NJS…