FM Towns Marty controller question

A friend of mine just got a FM Towns Marty. It didn't come with a controller so he asked me to convert a Mega Drive 3 button controller for him.

Easy enough as I found this handy diagram on GameSX:
http://gamesx.com/wiki/doku.php?id=controls:fm_towns_controller

Unfortunately I have my doubts that this is accurate. On the Mega Drive-controller Pin 8 is GND and according to that diagram it's 9 on the Marty. And my friend says that the Up, Down, Left, Right and the B button on a Mega Drive pad works on his Marty already. Doesn't that mean that the diagram of the Marty pinout is wrong, and that pin 8 on the Marty is actually GND too?

He only shipped the controller because the system is heavy, so I have no means of testing the controller myself.

Any help would be greatly appreciated

 

Any thoughts on this? I have left the GND on pin 8, as I find it most likely that it'll work.

 

My friend received the controller and it works. So unless the FM Towns' controller port differs from the Marty's, the diagram on GameSX is wrong. Pin 8 is ground just like the Mega Drive