It is very usual that delegates (members of postal administrations) present each other presents. Very often in the form of a presentation pack with the latest issues of the country. Most of the time the value is the pack itself and not the stamps which are offered. But, there are exceptions!
In 1947 the delegation of the postal administration of Dutch East Indies offered the delegates at the congress in Paris a souvenir pack with 60 of the latest stamps, including postage due stamps. But, the stamps in this pack are not all ‘every days’ stamps. Among them the Konijnenburg issue 35c and 5 gulden. With a catalogue value of € 200 and € 400 really not the most common stamps.
The 35c is printed in 12.200 copies and the 5 gulden in only 5.000 copies. And, take into consideration that both have been partly overprinted in the Japanese period. Real gems!