WSA-M2C195-A was Mercon transmission fluid. Any power steering unit that calls for WSA-M2C195-A was serviced with Mercon transmission fluid. Ford no longer makes or licenses Mercon fluid--they started making "power steering fluid" which meets the specifications required for power steering systems that were serviced with Mercon.
However, Mercon compatible fluids continue to be available in the aftermarket, and these can be used to service those power steering systems.
Chevron MD3 is recommended for Mercon applications. As power steering units tend to be less fussy about their fluid than do transmissions, I would not hesitate to use Chevron MD3 in a Ford power steering unit that calls for WSA-M2C195-A.