I have reviewed some reference material and found the following
Option A04 - Basic Radio Group, Avail 69-71
power brakes, front air foam front bench seat, LH outside remote chrome mirror, windshield wipers 3-speed variable, power windows, music master AM (or any of the following radios; deluxe AM, AM/FM, AM w/stereo 8 track player, search tune AM/FM, AM/FM multiplex-stereo, AM/FM multiplex-stereo w/8 track player) Power antenna, power steering, deluxe wheel covers (class 1 or class III)
also found A53 - TA/AAR which only says rear mounted antenna
there are 2 other codes; not sure if these codes were ever used on E bodies
R48 - power antenna
R45 - oversize antenna
there is mention of a telescopic and a fixed antenna but no codes.