Yes, there were two PH-POL’s.

The first was ‘yours’, ex MZ138.This aircraft was Dutch airforce serial R-2, then registered to the National Police Department at Schiphol on April 18, 1955. It lasted just ten days (!) and was written off in a nasty stall accident on landing at Ypenburg on April 28th, 1955.

Its replacement was NX537 (later Dutch airforce R-17) which was registered PH-POL too, in mid June 1955. It went through a variety of owners (including a museum) until it ended up in the UK (in 1991) for rebuild. It is now flying apparently as G-BUDL.

Hope this answers your question.