Oh sure...NOW the picture is showing up! At least I guessed correctly! :laugh:
In the UK after 1 August 1967, the number plate year began around August rather than January, so it's also likely that a fair number of late GT6 Mk3 cars are commonly referred to as "1974-registered" cars.
As for anything in the US, by that time the cars likely would have to have been considered 1973 models regardless due to Federal safety and emissions regulations. Leyland was killing off the GT6 due to low sales, so it would've made no sense whatsoever to go to great expense to have a handful of GT6s meet the 1974 bumper standards (which included slight front reinforcement and major additional outriggers and reinforcement on the rear of the chassis, as well as the big rubber overriders themselves).