There are POV videos for every ride at Universal (and Disney) on
YouTube, so I don't really think there are any restrictions for recording (except when maybe before a ride is officially open - for example there were no Hagrid's videos up and there are no Velocicoaster videos up now because that ride isn't officially open yet -- perhaps it's a violation of the passholder agreement or some such thing, and all the big bloggers and orlando vacation sites don't want to violate that.
Do you have a harness for your gopro? I'd probably go that route rather than hopping on a ride with a gopro attached to 3-way or tripod/grip handle.