Exactly so.
But then comes the usual shriek to that helpful copyeditor, Don’t Fuck With My Copy!
seems rather pedantic. Like 'plane and 'bus - both of which you used to see, but don’t any more.
I just read a book where Roman Numerals were followed by a period, as in “Napoleon III. then declared war…” or “Louis XIV. declared his support…”
(Fyffe, History of Europe, English, about 1878, free on Project Gutenberg.) Interesting stylistic nuance…
(The writer also uses the term “milliards,” which isn’t much used these days…)
Trinopus
My guess is that it’s something like the German style of putting periods after numerals to indicate abbreviated ordinals. “XIV” is just “fourteen,” but “XIV.” is “fourteenth.” I suppose you might avoid the the abbreviation by writing “XIVth.”