Churchinchow,
As it's a Tuesday you're flying, it is almost guaranteed to be a 747. 777-200ER's operate on Wednesday and Sunday. The 777's tend to be GE powered and these are progressively being refitted with 777-300ER style interiors. Every passing week, there is a slight increase in chance of getting one with New First and AVOD as the fleet gets the refresh. Doesn't affect you though as you're off on the Tuesday.
As for your chances, well it's a mixed bag. It's not guaranteed and will purely depend on aircraft availability. If you message me 1-2 days before, I'll tell you the reg and what config the aircraft is fitted.
Champ