I'm building my first kit too. Although I haven't had to yet, titebond can be taken apart using heat from something like an iron.These were glued using titebond and I'm guessing it's not easy to free them now!
What I'd want to know is if the gap is due to the ends not being square, or if the sides slipped while being clamped ( wet glue is a great lubricant, so stuff can look good clamped dry, but when the glue is present its easy for the pieces to slip when clamped).
Lay your glued up sides on a flat surface and see if it lays flat. I'm still working to understand the geometry, and where it matters most, so I typically go overboard in trying to keep everything aligned.
Mitch