To go on the record once more... the process that Mike followed to create these Zeck/Zimelman creations was that he would pencil a smaller "finished" prelim and then he would use an Artograph to enlarge the prelim and re-draw it on the larger board on which Zimelman would paint. He did this for all five Punisher Limited Series posters, the first two Punisher posters, this Cap vs. the Mob poster and the 50th Cap anniverary poster, the Iron Man poster, and the Punisher: Return to Big Nothing Hardback cover. The painted versions of the Punisher Graffiti poster and Cap Annual #8 poster were painted over bluelines since those pieces had been previously published. He continued to use a similar process for the Byron Preiss novel covers and Marvel trading cards he did, but those were done smaller. Some of the "finished" prelims were later inked by Mike and sold or gifted like this piece, the finished prelim for the 1st Punisher poster, the Punisher #1 & 3 covers, and the Big Nothing cover but some of the finished prelims still remain in their original pencil format like the Punisher #2, #4, and #5. All the Punisher Limited Series finished cover prelims can be seen in the Mike Zeck Artists Edition.
I'll note that the painted plates from the 1st Punisher portfolio and the color interiors for Kraven's Last Hunt and Punisher: Return to Big Nothing were all painted over blueline art.
And, you can see and hear a little more about Zeck/Zimelman paintings by watching the show and tell from Felix Liu's January 21, 2019 podcast: https://www.youtube.com/watch?v=jys5z2pl0Es