I believe so. The movesets listed are optimal for PvP.
No one is able to do a real analysis on PvP without knowing how mega works. Just a simple change on moveset or CP calculation will change everything.
As examples, if they add shadow claw and dragon claw on a 6000 CP Mega-Rayquaza, we will be seeing a lot of those and less giratina. If no moveset changes and only a small increase in stats, we won’t be seeing many Mega-Rays at all. Or, what if mega is based on best buddy and you can only bring one to PvP, then you will have to pick one that covers rest of your team. Again, it all depends on what Niantic decides to do.
Some have predicted the CP for mega evolutions. Again, they’re speculations only.
All you can do for now are saving the Elite TMs, candies, and stardusts