To bring this back to life, it appears CBS's first GE color film chains would have been the PE-24 class - as they delivered their first 4-V color chain to the network's Broadcast Center in New York per this link to a Broadcasting magazine article in its April 26, 1965 issue when their line was the PE-24 (and about a year before they developed the PE-240 - the first references to which were in a GE ad in the March 21, 1966 Broadcasting):
https://www.worldradiohistory.com/hd...%20electric%22
I was right, though, about both BC and Television City using GE chains.
But Broadcasting has also been illuminating in other ways. A July 18, 1966 article noted that while WCBS-TV, having access to network facilities, was already loaded for color, WCAU-TV ordered RCA TK-42 cameras; WBBM-TV, KMOX-TV and KNXT all ordered Marconi Mark VII's - and all four would receive or had received RCA TK-27 film chains:
https://www.worldradiohistory.com/hd...rca%20tk-27%22 (p. 54)
https://www.worldradiohistory.com/hd...t%20marconi%22 (p. 55)