You're right!
Good to know. I'll revisit the Molex site.
Meanwhile, I've found a source for TinkerKit pre-wired connectors at Robot Mesh.
They have various lengths of 3-pin & 4-pin female units and separate 3-pin male headers.
https://store.robotmesh.com/microcontrollers/arduino/tinkerkit/tinkerkit-wires-20cm-8in
Thanks for following up. Much appreciated!
Following up from the Molex site:
These connectors are KK254 series and are available pre-wired to the connectors.
You might have to search for a distributor, but I've included a relevant Molex link:
Molex Connector Part Number - 217797-1031
Hope this helps!
Thanks to all who contributed to this conversation.