Yes. Ghost-type moves will NEVER affect Normal types. While the same can't be said for Normal moves hitting Ghosts for Scrappy and Odor Sleuth exists, I don't think Ghost moves can ever hit Normal types, even if the Pokemon has an Item while Poltergeist is being used.
Poltergeist doesn't have any special interactions with the type chart, so yes.
Source (the other answer)
However, you can also use the Ring Target, but it's not a reliable gimmick, and you probably have to waste a move for something like Trick, Switcheroo, or anything like that.