
Here's another page from the Heroes World Catalog, and what I want to turn your attention to is at the bottom of the page...

Ah, there we go! In the 1970s, comic book back issues began to gain in value, and the first speculator's boom began... (and I apologize if you're not comic book geek enough to understand any of this). It began with DC Comics' Shazam! #1, and continued with Marvel's Howard The Duck #1 and the DC Tabloid-Sized Superman Vs. Muhammed Ali! Speculators intercepted a lot of these books before they could hit the newsstands, hoping to turn a profit on them quickly (the same thing would happen again in the late 1980s and early 1990s, with stuff like new X-Men books, the Death of Superman comics, and more).
Anyway, somewhere along the line, as you can see, someone stocked up on first issues of various Marvel Comics titles and packaged them as you can see here! And that included the first issue of Marvel's Godzilla comic!