4 Pin Connectors / cable

[stego]

My Mk1, '73 suitcase, has male connectors on both sides of it's Amplifier and Keyboard. Is this usual or was the instrument modified?
I bough it in London well over 10 years ago and it sounds as smooth as butter.
I now have to replace my Keyboard to Amplifier cable and have been told I'd have to change one end of my connectors, I;m not sure which though. Can anyone help?
'Siji