If it is proven that-that date has a different number thickness (on a considerable amount of the mintage) then a simple side note on the year would be enough.
If all that year mintage has the numbers different then surely the catalogs will update the date and give it a different KM# suffix ###.1, ###.2 and so on.
So we either have to be sure how much of the mintage is affected by the difference before making a change.
Numista referee for the "Viceroyalty of the New Spain" (most of it).
History through coins.
Eli V
