Absolutely possible. It potentially was dependent on the size of the monthly order and distribution for that particular region. Some newsstands received books a bit earlier than most. I have seen a few (June 62 arrival) AF15s, for example, with May 31st arrival dates. I have yet to see an FF 1 (August 61 arrival) with a July arrival date. I have seen a handful of FF2s (October 61) with Sept 61 arrival dates. DD1s typically have Feb 64 arrival dates, but I have seen plenty with January 64 markings. The distribution time difference (from cover to actual release date) seemed to be smaller with golden age books and larger with Silver and Bronze. That probably had something to do with the mass printing for Independent News for Marvel/DC then Goodman switched over to Curtis Circulation Corp (CCC) in 1968-69 to expand the monthly Marvel title distribution (I think it went from 9 titles a month to 15), thus the explosion of Marvel titles in 1968.