I think this is the simple answer to my simple question.If a translator is paired with an AM station it has to "translate" the AM 100%.
So technically the HD transmitter we could say is the "originator" due to AM740 being a daytimer
Exceptions to this might be that the AM station would not have to run supplementary signals such as...when the AM is on it must carry a perfect simulcast of it.
Exceptions to this might be that the AM station would not have to run supplementary signals such as
C-QUAM or HD stereo, RBDS, time codes, or orange alerts in order for the translator to translate the master station in stereo,
or do any of those other things, maybe even including the slipping in of an SCA stream or two.
I do not know whether these guys are in stereo, but I doubt that their AM is.