@4 No, those are comic pages. There is a seperate achievement for those and they should not count towards this achievement. I think the reason @3 may not have all magazines is because they have not completed the levels in the sewer. If not this may have just glitched. unlucky?
Like most everyone, I find collection achievements annoying because I am so obsessive compulsive that I have to collect everything. Thankfully, I think I'll enjoy it with this game since it is so much fun to swing around as Spider-man!