Read Thread: What Counts as a Different Box?
I think it depends on how you present it. Normally, with boxes that close together, I'd expect them to be a series, but if you have some reason you think they should be individual boxes, then I don't see why you shouldn't be able to present them that way. Are the stamps related, thematically, or do they tell a story? Then I think a series makes more sense. If the stamps are unrelated, or if finding one doesn't depend on finding any of the others, then I think individual boxes can make sense even if they're close together.