BingBongBoy is correct.

There are currently no plans to fit any 767s with the NGCW cabin.

You will have AVOD. The 767 fleet was the first to be fitted with AVOD.

CW on the 767 seats 24 pax, so cabin service tends to be quicker, although if you're on a sleeper service it probably won't matter. Bear in mind overhead lockers on BA 767s are considerably smaller and this might create an issue if the flight is full, or if your carry-on is a bit larger than normal.

Other than that, I'll leave it to regular flyers to advise you.

Have a good flight!