I do believe they are glued. Opening the cable management tabs (not sure what they're actually called) we'll give you access and room to attempt to pretty it apart. There are videos on YouTube, and most likely a tutorial here on iFixit.
I do believe the max size HDD is a 750GB. 1TB might be too big. Though the ONLY place I found this stated was on iFixit. No where else.
Good to know, thanks!