I can at least shed some light on at least when the Sun boxes supported it (which may or may not help narrow down the date)

The initial Sun 1/100 multibus machines did not support virtual memory.   I have one of the last (if not the last) original multibus boards

from Sun with the original PROMs...  and it was supported up to Sun OS 0.7.    This OS was based off UniSoft UNIX v7.     The 0.7 version was released in 1982.

In order to support virtual memory systems, there was a board upgrade required.   Anyone who wanted to go to SunOS 1.0 had to get this board upgrade (which from what I know, was a board swap... not sure if money traded hands as well... and is one core reason the original boards are rare).   The release of Sun OS 1.0 was in November 1983.

So, Sun OS didn't see this until late '83.

Earl