Costa Rica 15 & 25cts 1952 Queen Isabella imperf proof - reverse banknote proof

Description

Very rare imperf proofs of the 15 & 25cts (only values known)1952 Queen Isabella of Spain issue (caravels of Columbus ), printed on the reverse of Uruguay & Pakistan banknote or stamps proofs and some item related to United Nations.
Engraved by Thomas De la Rue to commemorate 500th Queen’s birthday
Condition shown at pictures.
Worldwide shipping by registered mail .00 through Correos de Costa Rica, considering that communications to some countries are progressively getting back to normal.
I do combine shipping costs.
Paypal only.