All of the pieces are reuses, although AFAIK three of them originated in relatively recent Pyramid covers.
Starting at 12 O'Clock on the front cover.
Martial Arts, p. 227
Martial Arts p. 235
Monsters (3e) cover
Pyramid 3/82 cover
Fantasy, p. 83 (mirrored)
Pyramid 3/83 cover (centerpiece)
Back Cover left to right:
Pyramid 3/85 cover
Supers Mixed Doubles (3e) cover
Martial Arts, p. 161
The Monsters and Mixed Doubles pieces also appeared on the Basic Set covers. The bottom right piece on the back cover was also featured on the Mass Combat cover. All three of the Pyramid Covers appear to be part of some multi-cover deal with
Brandon Moore where the covers are also included as a full page within the magazine with no overlay text (good for printing/framing) as well as a short blurb directing people to Brandon's website.