Yes.
Sometimes my local Kroger carries whole briskets, cryovac-ed as @bump describes, but otherwise you might want to try a butcher.
Briskets can come whole, which means a ‘flat’ and a ‘point’ cut together, or you can just buy a flat. A whole brisket is huge, and it’s difficult to cook the whole thing properly since the point is thicker than the flat. So you might want to start out just cooking a flat.
The key to BBQed brisket is getting it to an internal temp of around 200F so that the collagen renders and it’s fall-apart tender, but don’t overcook it and dry it out. It’s more unforgiving than pork shoulder that way.
I started a thread early this past Summer and got a ton of great advice about how to up my brisket game…here it is if it helps: