At the time, this was considered a one-off from Berni Wrightson. Presumably, he attempted to sell it to other publishers before it landed at Heavy Metal. Another strip with some of the same characters shows up in the back of one of the early Dreadstar issues from Marvel’s Epic imprint later in the 80s.

(Heavy Metal issue #39, June 1980 – Page 56 Captain Sternn: Featuring Hanover Fiste by Wrightson)