A small footnote: in his Attack of the Living Dead: Earl review, Poe said, "Yes, in what may be an action figure first, Earl has removable intestines. They're rubbery and disgusting in the great tradition of gross toys."
Yes, it is a great tradition, but "action figure first?" That's not entirely accurate. There have been a handful (ha!) of figures over the years that have done just that, starting in 1998:
1998: McFarlane's Monsters playsets: Frankenstein's monster
1999: Spawn 13: Hatchet
1999: Spawn 13: Raenius
2000: Spawn 17: Clown III
2002: McFarlane's Monsters: Werewolf
2002: Attack of the Clones: Acklay
2003: Twisted Land of Oz: Cowardly Lion
2003: Empire Strikes Back: Tauntaun
2006: AotLD: Earl
2011: Walking Dead: Lurker Zombie
2012: Walking Dead: Well Zombie
2013: Walking Dead: Penny Blake
That makes Earl an "action figure ninth," at least! Anyone know any more?
The Taun Taun in the 2003 Saga Multipack came with some sparkly rubber guts.
You could almost include the X-files human victims from the movie line.
From Kaiyodo: Their Revoltech Fist of the North Star line had a Zeed thug who split apart and had hinged guts that are really easily removable.