well, writings on the amps look different to the ones I had all the times... the stuff is cheap in my country though so hopefully you got the real ones... this prop was the most popular stuff is russia so we have fakes on them available at the black market...
Doesn't really rub off easily. However, I use alcohol swabs to break the ampules (Just trying to be extra sanitary I guess)...writing comes off easily when the alcohol hits it, but I'm sure that's normal with any ink.