I'm looking for information about this issue. My question comes from that wonderful area of catalogs not recognizing this stamp. Edifil does recognize the stamp as #129pn. None of the other catalogs even acknowledge it. He was the "eleceted" King serving in Italy and abdicated in 1873. I have a couple of these used and I'm trying to figure out what to do with them. Were they declared to be cinderella's? Or Government in exile?
They are all proofs of an unissued design. They can be found both imperforate and perforated and there are many for sale on eBay and Delcampe with asking prices in the single dollars for the most part.