I recommend using the personal comments field to make note of the difference in the two dates. I am not sure there is enough of a difference in the size of the dates to justify an entry for a large date and small date. Usually these differences are much more noticeable, and I was unable to find any reference to a large and small date for 2008. I will follow this post and welcome any input from other Numista members.
They look identical to me, it only seems as the metal is simply giving away and flattening, also, note the separation between the core and the ring on the one on the right, might be that a lot of fake 1 Pesos are rolling around without anyone noticing, as it is supposed that the union must be smooth and flawless, but again, might just be the metal being exposed to temperature changes, as transfers temperature faster.
But might also be a lower - higher date that would eventually be added by Krause. There is another interesting date in the current set. The years ending with 8 in the 10 Peso coins tend to go all the way to the core, with the 8's under-belly being on the core when it should be on the ring completely, but this would mean having to make the number smaller.
Numista referee for the "Viceroyalty of the New Spain" (most of it).
History through coins.
Eli V