You should find listing for both a "tall narrow date" and a "short wide date" for 1975. These correspond to the left and right images in your post, respectively.
You know why there is so many tall / low, narrow / wide, closed / open number, dates during that period of time in Mexico?
Nop, there weren't operating the machinery while drunk.
It is because Mexico during the 60s, 70s, and 80s had two Minting houses, one at Mexico City and the other at San Luis Potosí.
Sadly, both used the Mo mark instead of the historical Mo and SLP, so if you get both date variations you are actually getting two different "Mint marks".
Then Mexico City Mint house closed and only SLP remains, but it keeps using the Mo to give the coins the patriotic Mint Mark instead of giving them the SLP and people knowing our coinage isn't actually produced at Mexico City, but actually on another city. If you ask to anyone where do our coins come from, it is sure they will answer "Mexico City of course". Most people here in Mexico doesn't even know the Mo house has been closed for over 25 years.
So those coins with date variants are nice to see as it is the way you can tell there where two Mint houses working at the time and that in some years they didn't shared their dies but each one crafted their own one. Check the coin sheet for Notes of the differences of some of them, and you will see that not only the date number where different in some of them, but that there is actually a whole list of difference in some.
Numista referee for the "Viceroyalty of the New Spain" (most of it).
History through coins.
Eli V
