Letters page replies by Roy Thomas. Cover says "Now on Sale Monthly!" indicia still says bi-monthly.
Cover is credited to Rich Buckler/John Romita at Heritage Auctions, although only Romita's name is on the cover. There is white out above Romita's name, so it is possible that Buckler pencilled the cover and Romita inked and provided numerous alterations, as there is evidence of white-out on many figures. Info per Nick Caputo.
Brain Drain note from Fred Snyder via the GCD Error Tracker.