This stamp has several majore plate varieties. The most common has a small scratch in the lower left numeral. It is common enough for me to posit that this plate variety is in one of the master dies, and should be found more than once on the plate(s).
This second plate variety is also common and has a dot in the oval. It is a candidate for showing up more than once on the plate(s).
This one has some ink below the E of REPUBLICA. It is very rare, therefore likely not repeating.