There aren't multiple NoDo updates for different OEMs. The one NoDo update has updates for all OEMs if they actually submitted them to get packaged for NoDo. For example, if there is a firmware update for the HTC Surround in the NoDo, that firmware update will only run if the device is a Surround. On a Focus, the firmware update will know that its not need and just not run and NoDo continues doing its thing.
while that sounds pleasing... Would you mind stating how you know this?