Interesting and that sounds quite plausible.   CCA sold it at one point.  Masscomp (because Steve was working for us) got a license and a redistribution license.   IIRC: we could redistribute the binary for free as long as CCA got Steve's changes back.

Steve definitely did the terminfo/lib work for CCA Emacs at Masscomp, as I had pointed out that AT&T was moving to terminfo but was locking it up inside of the System V (AT&T 'consider it standard' stuff - much to a number of their own people telling them not too).   Pavel ?? Curtis I think ?? - I've forgotten his last name -  had written a new uncontaminated version at Cornell that was a functional replacement and that could read the AT&T ASCII database and compile them properly.   (I don't remember if Pavel's version could take the AT&T binary versions).  I had obtained Pavel's version and we were shipping that as our terminfo/lib implementation on the Masscomp boxes and were switching our code to use it, as we had not yet signed a System V license and were shipping on a System III based one.    Steve started to include Pavel's library in the CCA version, which he got from me. 

On Tue, Jun 11, 2019 at 1:12 PM Lars Brinkhoff <lars@nocrew.org> wrote:
Clem Cole wrote:
> 1.) Zimmerman EMACS (a.k.a. CCA EMACS) ran on the PDP-11 originally
> when Steve wrote it at MIT.

I have this on the origin of Montgomery and Zimmerman Emacs:

  "[Montgomery's] emacs implementation was begun in 1979, after having
  left MIT.  I made it freely available to people INSIDE of Bell Labs,
  and it was widely used. It was never officially "released" from Bell
  Labs."

  "Unfortunately, several copies did get out during that time, mainly
  due to people who left Bell Labs to return to school or gave copies to
  friends.  When Zimmerman modified one of those copies as the original
  basis for CCA emacs, AT&T and CCA had a prolonged debate over it.
  Eventually the matter was resolved when Zimmerman replaced the last of
  my code"

https://github.com/larsbrinkhoff/emacs-history/blob/sources/Usenet/net.emacs/btl-emacs-2.txt