The buttons for those switches are still stocked by digikey and their manufacturer part number is BTN MDP nn (Where nn is the 2-digit colour code).
See here.
https://www.digikey.co.uk/products/e...=1&pageSize=25
These are actually the type of switch and cap fitted to the keypad my MK14 has now, but at the time the caps were only available in red or blue so I couldn't have the command keys picked out in a third colour so I made the numeric keys red and the rest blue.
I keep thinking I should get a few slate grey ones and redo the command keys in that colour as I would have done originally. But then I think.. this has been the machine's keypad for most of its life... I shouldn't mess with it now.