When I click the link in the datasheet for the M.2 connector, it shows an image of a different M.2 connector key slot. Which is the right one to select?
Use M.2 with Key Style “E”
The “key” is in the part number:
Here is the part on the manufacturer’s site.
https://www.amphenol-icc.com/pcie-m-2-mdt420e01001.html
Images on supplier websites may not match part number
On Digikey and other supplier sites, the image of the part doesn’t necessarily match exactly with the part number. They use the same image for the different key variants of the M.2 connector.
Use Hardware Github Repo for specific part information
All part numbers are listed on the BOM for each Notecarrier design. Navigate to GitHub - blues/note-hardware and for each Notecarrier variant there is a folder that contains the bill-of-materials (BOM), schematics, and 3D models.
For example, the M.2 connector is listed as MDT420E01001