Suction Regulator/Valve for early PA24-250 ( sn 304 )

[Stephan Mackenzie]

I have an early 250 and I think my Suction Regulator is heading south...

It appears to be the old Sperry type ( parts book image looks correct and lists part number 492 059 )

These are no longer available, can I go ahead and replace it with the PMA part from the Rapco catalog? Or do I need a Canadian equivelant of a field approval?

Any suggestions ( including where the original part might be available ) is greatly appreciated.