That's correct. Although it was 1969. I just sent Dave the paper from the IEEE Annals of History of Computing: 1058-6180/15 [2015] Called 'The Production and Interpretation of APRANET Maps" by Fidler and Currie

On Tue, Dec 4, 2018 at 3:45 PM Dave Horsfall <dave@horsfall.org> wrote:

The ARPAnet reached four nodes on this day in 1969 (anyone know their
names?); at least one "history" site reckoned the third node was connected
in 1977 (and I'm still waiting for a reply to my correction). Well, I can
believe that perhaps there were only three left by then...

Hmmm... According to my notes, the nodes were UCSB, UCLA, SRI, and Utah.

-- Dave