Third printing is clearly labeled in the indicia and also has only the US price on the cover, not British or Canadian prices. The third printing also has the CCA stamp which is not on the 1st printing's cover.
Keith Williams is credited on the letters page only. Jim Owsley is credited on both the story sequence and the letters page.
This issue is a variant of
The Transformers (Marvel, 1984 series) #7 [Direct].
There exist further variants: