Yes, he did.

Did Swamp Thing appear in that episode at all?

Sure can. The episode deals with a film crew coming into town to film the TV movie, "The Latent Great: The Anton Arcane Story". The film crew and management are played by the writers, directors, and producers of the actual Swamp Thing show at the time. There are fun jokes about cheesy dialog, low bugets, and campy acting. It was like you were watching the people involved with the show having a good time, while saying goodbye to their current prodject. Hopfuly, if or when this is relased on DVD, this episode will have commentary with it.

When you say inside jokes, what do you mean? Could you give a couple of examples?

Yes, they did "wrap" it up. The last show is full of inside jokes, so if you payed attention, you would get all the inside jokes in this episode.

I can't remember, but the last episode it titled "It's a Wrap". so i guess so from the title.