Q u o t e:
not that its really important but I know I still have 2 trinkets that dropped from direbrew. it seems this achievement should fit into re retroactive category

For the most part the only achievements we made retroactive through loot were in raid dungeons. We figured it wouldn't be terribly difficult for a lot of players to get a 5 person group together and do some of the 5 person dungeons. I'm pretty sure Direbrew will be beat up a LOT in this next Brewfest.