I was wondering if anyone can tell me anything about the blue marbled Duofold in these pictures, which contain other pens for comparison of size, etc. The Lapis Lazuli is definitely a pretty modern Centennial (not sure about the exact dating of that, either). The vac is not a full-sized major, and the Sonnet is, well, a standard Sonnet size.
Couldn't find any Parker date codes, and that flimsy top of the section has me worried a little bit. It is authentic, isn't it? I bought it thinking it was an International, and I was guessing no later than the early 1980's. But that is mostly a guess.