Doug Gilford
Doug Gilford's MAD Cover Site

Not so obvious are a few obscure border references. An early group of issues (#27 through #30) had non-evil seeing, speaking, hearing — political monkeys.

Border detail from MAD #27 to #30: see, speak and hear no evil monkeys

Much later in #357's border was what a French King Kong might look like.

Border detail from MAD #357: a French King Kong

Thanks to José for the question suggestion.