When adult Bill visits Georgie's grave, one of the other headstones is that of Peter Terranova. This indicates that the stone is a re-used prop from "Wiseguy" in which Peter Terranova is the murdered brother of lead character Vinnie Terranova. See more
[to Bill, Ben, Beverly and Eddie about going into the sewers to kill It
Oh come on, guys! What the hell are you gonna do now? Sing Kumbaya? Wake up. Take a breath. Do you smell that? That's death. It's not for Stan. It's not for Mike. It's not for Henry Bowers. It's for us. It's in the air. Losers fight It, losers die. And you know that, don't you Captain?