In the scene where Harlow and her roommate (Una Merkel) are exchanging pj's, there is a shot where Una passes the blouse to Harlow and on the left bottom side of the screen I could swear that I saw nip. I paused it and it sure looks like it.
check out the book "Sin in Soft Focus" -- great book filled with similar films that showed things that were strictly verboten just a few years later...
I have been in a real pre-hayes kick lately. They come every so often, like an addiction. I'm mainlining them right now. One that seriously sticks out from the recent ones, is "Night World" with Karloff, Lew Ayers and Mae Clark. This thing was SENSATIONAL! Not only in it's very adult materiel but also in the direction and acting. http://www.imdb.com/title/tt0023271/
I paused it on a 55-inch HD and could clearly see she was wearing some type of camisole. The nipple looks like a bit of fringe near the top. Everyone seems to go on and on about there definitely being a nip, so I thought I must be crazy. But my first hunch I'm right is that her nipple would have to be sideways on her breast to be sticking out at that angle. Sorry to burst the bubble of people looking for nip shots that are 80 years old.