There is a L4D Sacrifice comic, about what happens to the L4D survivors between L4D and L4D2, when they meet the L4D2 survivors. The comic shows a image of, Chuck Greene?
Is that Chuck Greene or am I seeing this wrong. Why would it be in the comic?

That is, indeed, Chuck Greene in the third panel.  Left 4 Dead and Dead Rising have been poking fun at each other for ages.  Dead Rising had Zombie Genocider as an achievement, Left 4 Dead had Zombie Genocidest, which literally 1-upped the Dead Rising achievement criteria, Dead Rising 2 continued the tradition.

I think it was Frank West that left graffiti in a safe house in the first L4D2 DLC. It's been awhile, though and I could be mistaken.