I believe it was 50and retired that just bought the tool for his 2011 Acadia I believe.
This item you have to call in to request-- I think 50andretired said he got his in about 3 days....
Just to set the record straight I have a 2010.
I believe that it will work on all GM vehicles with TPMS.
I ordered it on a Tuesday and received it on Wednesday
It came from Chicago, which is usually a 1 day trip to MI.