This is the most common plate variety I find. It is most likely present in every repeatable block of dies on the plate. I do not know what the size of the master plate is, but usually it is 2 rows by 5 columns for the large format values. This plate variety alone tells us that all of the late issues share the same plate since I find it on the cream frame printing of 1951 (2p1L), the clay printing of 1955 (2pCL2) on the same colors as the 2p1L, the rust brown 2p1L5z Zarate printing of 1956, and the 1957 2p1L6 printing.
This plate variety also has a line break to the outer frame along the left side of the stamp. There are some ink dots found on some stamps and not others, but these are not repeatable as far as I can tell.
I also find it on the SERVICIO OFICIAL 2p1L5z issue.
