In my collection, the newer ones (about 2015 and beyond) do not have HKDNP, whereas the older ones do. According to
https://historiek.net/mooie-borrelve...huisjes/38814/ and
https://zakenreis.nl/reistips/sterke...bij-de-borrel/ (in Dutch), they have been manufactured in Hong Kong since 1995. Additional interesting info about KLM huisjes is at
Postzegels en KLM huisjes verzamelen. Port Betaald, port in NNG en Mercurius proef Page 5. (also in Dutch).