No documentation has been presented concerning these.
The only known set comes complete and stuck on paper.
All stamps have 4 holes in a diamond shape (or 4 holes on 1 pair)
Our guess is these were perforated by some postal authority and sent to another postal authority, probably a colony, to show design of legal stamps.


1 or 2 perforations/ stamp. It is noteworthy that 25B green/black is included, which is somewhat doubtful (if these are perforated by a postal authority)

perforations hardly visible on image, but should be there, 1 perforation/2 stamps

Until further evidence comes along I´d say, doubt these, but give them the benefit of a doubt?