Thanks chaykinstevens . Magneto certainly does look more malevolent on the second cover.

I loved #49's cover color scheme (by Goldberg? no color credits in GCD); it certainly was a standout at the newsstand. The UK version's color scheme makes the cover appears a bit garish to me, but inasmuch as the interior pages were black and white I can see why they'd want to use more color somewhere.  (And the b&w pages inside must have made it that much easier to really appreciate the sheer gloriousness of Big John's pencils & inks in that story.) 

And per this site www.wymann.info/comics/056-Avengers-65.html I see the unaltered art was also used for Marvel Triple Action #41 and the German Avengers title Die Rächer #48.