The card has a black edge connector which i'm thinking is NuBus, having never seen one before though. I have seen PDS sockets before though and this sure isn't it. I took some pics, albeit with a phone, and as bad as they are they'll just have to do.

6100 Motherboard

The PPC 601 Gel

The DOS Card

DOS Card Connector

I don't actually have a monitor for the 6100 anyway, so I think this will end up shelved rather than put to use.