Thanks to commentator Jim K, I have focused on the Dell comics Space Man series. I have Space Man 2 (the original version of the 1972 reprint Space Man 10) as well as Space Man 9 (the 1972 reprint of Four Color Comics 1253, which was the first appearance of Space Man).
There are greenish-colored faceless cyborgs in these comics. I am virtually 100% sure that the cyborgs here are the ones I remember. The story line is roughly familiar.
The only problem is that neither comic has the panel I remember.
Two possibilities:
1. Space Man 9 is the comic I have been looking for, and my memory of the panel is confused. I may be mixing up the robot assembly line panel from Beyond the Unknown 25 with the cyborgs.
2. Space Man is the right series, but I have the wrong issues. This does not make much sense, since the remaining issues are from the early 1960s and were never reprinted. It's possible that in 1972 I had purchased one of these older issues from a used comics shop.
I think # 1 is more likely and that I have the comic I am looking for, but it is a bit of an anti-climax because the panel I have remembered for close to 40 years is not there.
However, I have ordered whatever available other issues of Space Man I can get my hands on, and I'll see if the panel is there (which would confirm # 2).
