There was a Heritage auction recently when a PCGS PR61 1931 2.5G Wilhelmina was auctioned:
https://coins.ha.com/itm/netherlands/world-coins/netherlands-wilhemina-i-proof-2-1-2-gulden-1937-pr61-pcgs-/a/3053-37819.s?ic4=OtherResults-SampleItem-071515
According to the listing this is the second known