Series was evidently originally revived in hopes of a TV show. In PM #2 letters column, the editor notes, "The pilot film was written by amiable Arnie Drake and made by Hal Seeger Productions... Negotiations with networks and sponsors are under way..." That effort must have fallen through, because later Filmation floated PM as a possible cartoon.
Publishing hiatus between #10 (May-June 1968) and #11 (February-March 1976).