Yeah, that’s the part I’m thinking of. I wonder if it’s an effected-up version of the bass harp, or perhaps some mix of instruments. I can’t remember where I read it, but I’ve read that the harmonica is in the second verse and in the instrumental at the end. It’s obvious where it is in the second verse, but I can’t quite catch it in the instrumental, so I’m wondering if it is those two bass notes.