A sticker on the switch plate has an 8428 date code, which would be July, 1984.
Wikified here: wiki/Cherry_B4VB-5601
Ha! I had forgotten about those switches but definitely not that keyboardEngicoder wrote: ↑Snuci posted a a black stemmed version of the same switch last year
photos-f62/vintage-cherry-solid-state-c ... 12584.html