Yup, that’s an external XM tuner. That pretty much confirms sometime after 2011 GM started using external XM tuners on all full size SUV even if they didn’t have Navi.
You’re good to install that 2 minute integrated $69 A2DP music / audio streaming kit from Crutchfield then.
Does your rig have the little Bose speakers on the windshield pillars?
I do have the Bose on the A pillars. Funny you mention that. My setup has the separates in the front (door and pillar) and coax in the rear pillars. I thought for sure the rears were in the doors. No biggie really, it sounds good.
Sidebar: Every time the wife and I go out to dinner, we both comment on how quiet the interior is. Sans teenagers makes a big difference in any vehicle
, but compared to my 96', there's no comparison. My Passat is good, but tinny depending on the road surface, and the wife's Beetle Conv, well that's like being outside!