Is there a way of finding out exactly which aircraft will be performing my flight today? The seat map has suddenly changed from what used to be a 777 with WT+ rows 21-25 to a 777 with only 18-20 in WT+.

I checked in yesterday and selected a bulkhead, now I have viewed the seating map out of curiosity and it is showing the new seating plan but with my seat assigned as 12G which appears to maybe be in CW. Wondering whether I have been favoured by teh upgrade gods or whether there is a system glitch and it's actually been changed to a 747 low-J.