The Lionel and Frisco 2-8-2 models are correct for the pre-WWI USRA standard plans which most railroads adopted for various wheel arrangements. A majority of 4501 models, in any scale, have always used the WWI light Mikado design, since it was easy to repaint into several different railroads. These two Lionel versions were created specifically for these models, and I don't think they will ever be duplicated again.
The light and heavy monikers were created by the USRA to distinguish the different 2-8-2 locomotives by weight. Both had that swell in the boiler by the firebox, a telltale sign of a USRA design.
