Colón pencil and Romita ink credits as attributed from Heritage Auctions and the auctioning of the original art, https://comics.ha.com/itm/original-comic-art/ernie-colon-and-john-romita... (retrieved 10 August 2019).
Nick Caputo doubts the Colon pencil credit noting that his earliest credited work for Marvel was in the late 1980s (per Bail's Who's Who). Nick suspects the cover pencils are by Rich Buckler, possibly from a Romita rough. Inks are indicative of Chan's concurrent work on Conan. Romita redrew the creature.