Well, not really the Comics Code per se–but this is the area where we look at how vintage comics were changed for publication, so this entry fits. On the right is the cover to MYSTERY TALES #38 as it saw print–and on the left is the cover as originally submitted by Bill Everett on Alan Class’s UK reprint in CREEPY WORLDS. As you can see, the Ice Man was totally redrawn and other details were monkeyed around with as well–in particular, the expression on the sailor at the upper right. These changes were the work of Carl Burgos, then acting as cover editor for the Atlas line of titles. Burgos is best remembered as the originator of the Human Torch in MARVEL COMICS #1, but he worked for Timely/Atlas/Marvel for years. As cover editor, he took a strong hand, often working over completed pieces well beyond what any reasonable person would have considered necessary.
For a full recounting of this situation, and indeed Burgos’ entire career, Dr. Michael Vassallo has written an incredibly thorough account on his web site, which can be viewed here: http://timely-atlas-comics.blogspot.com/2016/04/happy-100th-birthday-to-carl-burgos.html