According to the "Sterbebücher" (death records) of Auschwitz, Willem Lampie was murdered there on 8 October 1942. This date is different from the official date of death as determined by the Dutch Ministry of Justice after the war. For the time being, the website joodsmonument.nl, list only the dates of death, as published at the time in the "Nederlandse Staatscourant" (Dutch Government Gazette) by the Ministry of Justice.
Sterbebuch Auschwitz (death record)
Official death certificate nr. 118 for Willem Lampie dated 15 September 1950
(after clicking the link for the Amsterdam death certificate of Willem Lampie, please wait a few seconds until the website opens and the deed 118 is to see).