There is a detailed list on the French Wikipedia with the configuration of each aircraft: https://fr.wikipedia.org/wiki/Liste_...7_(68+2_cargos)
You can see there that 9 of AF's 77W have the Best cabin in Y and Y+ but the old configuration in J - so do not rely on the seatmap in J to infere what would be the experience in Y. Some others do still have the full old configuration (as F-GSQN)...

If you make a dummy booking on AF you should be able to see what to expect for your particular flight (except in case of last-minute aircraft swap). For instance for AF344 on July 17th, I would make sure to have a good book or a fully charged iPad.