I used to work with a Mexican man who told me also that Tuesdays on the 13th are the bugaboo.

(I've thought that the Friday the 13th superstition probably comes from the Friday that Jesus was killed; the 13th from the number of Last Supper guests. I really don't know- for all I know, the superstition has a much more recent and more direct cause.)

But, let's see: under the old calendar, you say, MMario, that
#1- the 'old' Friday became a Tuesday when the new calendar went into effect. (I haven't a clue as to how one knows that.)
#2: Mexico is preponderantly Roman Catholic.
#3 The Catholics are the one who changed the calendar.
#4- The hierarchy are the ones who held onto the knowledge that Fridays were now the new Tuesdays?
#5- Which means that the common people still hark to that knowledge?

huh? Maybe?