I believe the correct VAOS # is ZA4500. There were two types, #2B & 2C.
These are WT8 No. 2 keys.
Louis Meulstee has a free download available on morse keys at
http://www.wftw.nl/keyandplugv1%2003m.pdf
On page 8 there are photos of the Canadian key which has a 1940 date.