Dear friend. I can't really tell you much about AA 767-300 but I can tell this - I flew on a BA 767-300 ( with Rolls-Royce, those engines really sing to your ears!!! ) from NYC to LGW and it was one of my best flights ever had, the 767 is really a neat wide body plane and I'm sure you're gonna love it no matter what seat you have.
Good trip and after you come tell me about it!
CV990, the Maserati of the skies!