Blue Ox shows a different base plate part number for the Enclave vs the Acadia. I susopect the difference is just the shape of the fascia, since the chassis (unibody) is the same. You can probably make the Acadia base plate work on the Enclave by cutting into the fascia somewhere, but the one made specific for the Enclave & Traverse will fit better/easier..
2004 American Tradition; 2014 Buick LaCRosse
Homebase in the Ocala Nat'l Forest near Ocala, FL