That’s because it IS Allen Gustav Anderson. Unfortunately, there’s no signature to back up the claim. However I’ll find the cover of his that I have in my mind, which most closely matches this cover, and link it here so you can do a comparison. (If I don’t get sidetracked and forget all about it, that is.)
Looks like Allen Gustav Anderson.
That’s because it IS Allen Gustav Anderson. Unfortunately, there’s no signature to back up the claim. However I’ll find the cover of his that I have in my mind, which most closely matches this cover, and link it here so you can do a comparison. (If I don’t get sidetracked and forget all about it, that is.)
Compare to:
https://pulpcovers.com/the-second-slug/
Allen Gustav Anderson’s art confirmed.