The Wolfburg factory was closed last week and reopened today so it's possible notifications are a bit delayed.
I emailed my dealer today to get an update on my R and he says it's still showing as unconfirmed BW37. He says he's got another car (a GTD) that was showing as estimated BW36 last week, which today has just been confirmed at 36, and so he says they should be scheduling week 37 production during this week. So by that reckoning maybe BW38 will get confirmed after that?