I have a friend who is an older guy, and he tells a story of being in the original Forbidden Planet comic shop in Denmark Street, London in the early 80s and one of the staff there showed him several big stacks of copies of Silver Surfer #4 they had in their basement. They would only release one copy at a time upstairs into the shop though because it had that reputation of being particularly scarce and they could charge a lot of money for it. The fact that they had loads of copies in storage obviously speaking the fact that the comic was not particularly rare.