might have it figured out after a lot of looking found this bit about 4 pin sockets on sensor shields
"This connector can go to external Bricks or other devices that have more complex Communications Protocols to work with Arduino. Examples are GPS receivers, Ethernet interfaces, and other complex devices. These are 4-pin connectors."
There's no logic on these types of boards, they do nothing more than re-arrange the pins (and provide a lot of ground and power connections). Just use a multimeter and test continuity with each pin. I'm sure after you map out one or two, you'll see the pattern and know what the rest of them do.