Judging from {Images #3194866 & 3194867}, it would appear that Santa Maria pressing dates to about late 1966. After all, the "NONBREAKABLE" is still part of the label copy . . .
Also, back covers that show "meaningless" in the text in the right column as shown on {Image #3194863} is a second-pressing. Initially it read "meaningful."
Added back cover, labels variant (Santa Maria pressing) and a rare drawing (credited to 'Lambert') which came as as a bonus with a few early US mono copies in August 1965, and seems only to have been distributed in a handful of markets. Copies containing it originally had a circular red sticker on the shrinkwrap stating 'FREE! INCLUDES A STRIKING PORTRAIT SUITABLE FOR FRAMING'. The insert itself was visible under the shrink on the back cover. (source)