The fourth IETF proceedings (back when the Internet Engineering Task Force was an internet engineering task force) contains a list of the 143 second-level domains registered as of July 10, 1986.
Of the 40 listed .com domains, the following are not in the list in the OP article:
adelie.com
buck.com
cca.com
mecc.com
nbi.com
next.com
olivetti.com
proteon.com
pyr.com
rca.com
tmc.com
vse.com
One of the five listed .org domains is not in the article: csc.org
The one listed .net domain is cs.net, also not in the article.
Of the 40 listed .com domains, the following are not in the list in the OP article: adelie.com buck.com cca.com mecc.com nbi.com next.com olivetti.com proteon.com pyr.com rca.com tmc.com vse.com
One of the five listed .org domains is not in the article: csc.org
The one listed .net domain is cs.net, also not in the article.