I just sliced a part away so you can connect to the GPIO contacts...it's the same as this one https://www.thingiverse.com/thing:2334119
The USB cable in the picture is connected to the printer, I needed the GPIO ports for https://www.lisiparoi.com/
I've updated the case to fit M3 or M2.5 bolts through, just pick the lid and base with the corresponding M notation. M2.5 wont grind into your Rpi board...O, and do not overthigten.
The MK3 frame is a little bit narower, so I've reworked the lids for the MK3
Printed Bottem in PLA and Top in PETG...
4x M3x16 screws for the case
2x M3x8 screws for attaching the case to the frame.
The M3 Nut version needs 4x M3x20 instead of M3x16
The M2.5 Nut version needs 4x M2.5x20 instead of M3x16
First install the Lid.stl onto the frame using the two M3x8 screws. Then attach the Base_Raspi2.stl.stl to the lid using the four M3x16 screws.