All 3 of my 122s had air conditioning in them and none were factory installed.
I think maybe a company in Dallas produced a kit that was widely used for
a number of years, as most of the AC 122s I know of had the same system.
My problem has been that when the temp is 105-108°F (40-42°C) I can only get
enough engine cooling on the highway at fairly high speeds. Around town
the engine overheats badly with the air conditioning operating and even at
that the cooling is marginal. Probably a bigger radiator and a better fan
would help.

(My 63 122 had a different AC with the evaporator and blower in the trunk,
blowing up through the back panel under the rear window. It was better
than the later models but had a coaxial hose running under the car from
front to back that was subject to damage.)
--
George Downs, The "original" Walrus3, Bartlesville, Oklahoma