Frank Miller (att) Superman/Spider-Man II cover rough

The auction house had this attributed to John Buscema, likely because it was returned to him by the art department as penciler of the book. It is clearly not his work. The cover is credited to John Romita Sr and Bob Larkin, but this rough doesn't really look like JRSR to me, either. I believe it to be the work of Frank Miller. Al Milgrom, the book's original editor agrees, but cannot say definitively . Superman's pose (especially his receding arm), the Parasite's stance, Spidey's general form and mask rendering, as well as the handwriting all seem to point to Frank Miller. Someday I will try and run it by Frank and confirm.

On 11x17 tracing paper