:::*That would be OR by prevailing standards, yes, though secondary sources that establish the history of the concept and talk about the existence of it prior to there being a name for it might be usable to bridge the gap. What you'd need, ultimately, is a source that gives a good account of trans history across various changes to how it's been pathologized by the medical community. Once you have that and have used it to create a historical spine for the article you would be on better footing fleshing out any given moment of history.