Trevor wrote a very interesting and in depth article regarding the so called First Star Overprint on his blog. This overprint is really rare (much rarer then the Second Star Overprint) and not much is known about the historical background. Ceresa, who spent more then 40 years collecting and researching Armenien stamps, did not see much of these stamps and in his books he reprinted the passages from Tchilinghirian/Ashford.
As you can see, this overprint is rather crude and smudged. It easy to see how the catalog publisher decided that this stamp – which was almost never seen, and where no letters exist – is just a forgery. It is interesting to learn, that those overprints are probably much more legit than the Second Star Overprint, which looks much cleaner and better and thus became more present in the catalogs.
So if you are interested head over to his blog and read for yourself!