T-29s were trainers and C-131s for medivac and VIP transport - this one is a T-29 originally USAF owned and was then loaned to the US Navy from 1963 to 1975 before being retired.
When the navigator astrodomes aren't visible, cabin door location is different between T-29 (starboard side) and C-131 (port side) models. It was a challenge for transient alert crews insure they had the right model when VIPs were onboard so the airstairs would be facing the ramp for disembarkation.
Gary
Cottage Grove, MN, USA