Movie Classic #12-056-606 on cover, 12-075-606 in indicia. The center three digits of this code are the Series ID. Series titles that begin with the letters "Ba" are found in the 051-056 block of IDs, therefore the correct Series ID for this series is "056".
Although there is no month given in the indicia, the last 3 digits of the cover code (12-056-606) indicate a cover date of [196]6-06, i.e. June 1966.
This movie was released in U.S. theaters on December 16, 1965.
On sale date is Library of Congress copyright record publication date. Note that there is an error in the copyright record. It incorrectly says "4Jan65 (in notice: 1966); B239485". The "in notice" statement means the publisher listed © 1966 in the indicia, but the copyright office corrected it to 1965. However, the copyright office was clearly wrong in doing so. First, all entries in the records around B239485 are for January 1966. Second, as mentioned above, the cover code indicates a cover date of "June 1966" which indicates a 1966 release. Third, this comic was an adaptation of a movie that was released in December 1965.