Really? The only cover version for the second book that I've ever seen is the 'Bar of Unnamed Characters.' What does he alternate look like?
May 1984 First Printing has the bar scene with Conan and Doc Savage arm wrestling at bottom left and Bogart and Bacall sitting at the bar right in the center.
September 1984 Second Printing has a much closer (and better-drawn) picture centered on Doc Savage, The Spirit, The Shadow, Tarzan, and (I think) The Avenger playing poker while The Green Hornet, Lon Chaney, Indiana Jones, and many other famous faces look on.
My first thought was maybe they got in trouble using copyrighted characters and famous likenesses, but if anything the 2nd printing cover does more of that than the 1st printing. Maybe they just realized the bar scene art was not up to snuff compared to the poker art?