There does not seem to be master loot option for raids. I was unable to group in beta 4 error 90k so I could not check that. But based on the live letter it would seem that there is not.
Can anyone confirm this.
If this is true, I must say this is a bad idea. To coordinate who should need/greed or pass inside a guild group could be a PITA. While I think most guild mates will be honest and fair with regards to rolling, there will be those that won't be. Within most guilds there is a trial rank of some sort that has loot rolling restrictions for raids. In addition mistakes happen and people miss click. With master loot this is not a problem.
I hope there is a system in place that will/can switch loot to the proper character.
EDIT: I could not post until I switched my primary class to lancer, this was silly as I am a level 32 lancer 31 glad regardless if I select arcanist as my main class.