Congrats.
Serial number should be on the back or bottom. Call Mesa with the serial to see if it's been updated. AFAIK the update is only done in a factory setting. If the update has not been done, it will probably cost around $600, including shipping. Discuss with Mesa as they may have run out of the necessary parts.
To remove the amp from the rack case, remove the rear panel. The amp is essentially clamped in place. There are long screws that are inserted into the bottom of the case into a board that sits on top of the amp. Remove these screws to release the board. The front panel may sit in sort of a channel. I believe I braced the top of the amp with my hand and rotated the case so the amp will come loose from the channel. Then I eased the amp out.