Not really. "H" stood for Heavy Duty supposedly. As far as the 15x6" H-wheels, there were 4 different sized H's that I've seen. The A-12 cars & Hemi cars got the big H - 3 nubs, & flat bolt holes. Big-H wheels in the correct A-12 style were produced from 1968-1972. See this image.
i have pulled those exact style wheels from pickups and station wagons back in my junkyard ownership days, [1972-1984/85] when those vehicles were relatively new. if i had known back then those wheels were special, i would have charged more for them ! [20-20 hindsight ya know. ]