Type III stamps are co-mingled with type II stamps on the flat plate. The type III stamps have a very small dot midway along the edge of Rivadavia's lapel.
The second stamp is type III
I also find that the last A of REPUBLICA in many type III stamps has a small dot at the upper tip of the inside triangle.
Here are additional examples.
The first stamp is type III
... and so is the second one.