I read the information on these products some years ago, and for convenience's sake wound up going with Brownells' epoxy-phenolic based Teflon-moly finish
. For all I know it may be compounded by KG on an OEM basis. KG makes a Teflon finish as well as the Gun Kote moly finish. The convenience element was that Brownells' colors include ones that match their Parkerizing finishes. Since I was Parkerizing an M1 Garand with their manganese phosphate solution, I wanted to to spray the stainless gas cylinder with a matching color finish. That worked out very well.
I surmise that the thermosetting epoxy-based finishes have the pre-heat step in common, though Brownells is less specific, asking only that the part to be sprayed be "warm to the touch". I know from having been involved in a government project which had some painting problems, that primers and other paint materials frequently require very specific curing temperatures and times. However, I'm guessing that in the case of the thermosetting epoxy finishes that the preheat is partly to evaporate the carrier fast enough to make dripping less likely, and also to prevent the rapid evaporation from chilling the metal and introducing moisture condensate into the project.