It's a card containing sounds recorded from/modeled after the MT-32 designed for insertion into a modern module, obviously. Hence "vintage".
Well, it clearly says "PCM DATA ROM FOR MT-32 SOUND MODULE"
I've opened my MT-32, it does not have any place to connect this card inside either
I hope that's just a rhetorical device and you didn't actually do that.
What do you mean, did I say something stupid?
I've opened my MT-32 numerous times, to clean it and to replace a blown 7805.