58-0069 was indeed at one time a KC-135Q SR-71A refueler, had the KC-135R upgrade and subsequently became a KC-135T.
Lots of interesting information for anyone interested in tanker history here:
https://apps.dtic.mil/dtic/tr/fulltext/u2/a430855.pdf This reference mentions COMBAT LIGHTENING - the use of 4 x modified KC-135A for radio relay in Vietnam.
Multiple references - including this one - refer to it as COMBAT LIGHTNING - the use of KC-135A to relay information from the data fusion center known as "TEABALL" . Fascinating "space age" stuff for 1972 - including triggering the IFF on Mig 17/19/21 to reveal their location and feeding that to USAF aircraft in almost real-time.
Tails Through Time: Operation Teaball: Network-Centric Real-Time Intelligence During Vietnam
