Yes, they were overwing jet bridges, like the ones currently used at Schiphol. Although I boarded numerous 747s and other widebodies at the nasty old IAB, I never actually saw them used on the rear doors. I don't know if they were used initially--i.e., before my time--and then abandoned, or if they never worked. I always assumed that they were too difficult to use or maintain, but perhaps someone who worked at JFK can shed more light on the subject.
P.S.--welcome to the forum!
[Edited 2004-08-01 05:46:37]
Common sense is not so common. -Voltaire