Tony,
Bear in mind that CL were going to operate into airport as the first wide body charter aircraft so GSE was always a concern as well as runway strength.
So the airstairs were requested from Lockheed and magnificent they were !!
They were developed and tested at Rye Canyon and later on the aircraft. I have some pics somewhere !!
With the RR collapse the aircraft was delayed for over a year so the problem re aiports became less acute.
They were not used in service and I dont know what happened to them.
Olde,
Basic airline Tristar had a container baggae loading system in C1 and C2 ( C3 was bulk).
Because of the logistics problem - lots of destinations that did not have container facilities CL had no loading systems but was bulk loaded. As in fact also was LTU