That' looks like an incredible piece of meat. It looks too marbled to be flat. Maybe a hunk of point? CAB is supposed to be upper 2/3rds of choice and bottom third of prime. Either way that looks like some good eating
If it's not prime it's one gorgeous hunk of meat! We were in our discount market a few weeks ago and my wife wanted some petite sirloin for a stir fry she was making. This market is mostly Select and some Choice with their beef, but never prime. She called me over (from the beer department) and said look at this. It was the prettiest, most beautifully marbled piece of beef I've ever seen in there. It wasn't marked prime but it sure looked and tasted like it at dinner that night. You just never know.
Also not a guru, but I would certainly grade that a WIN for you, and a LOSS for the butcher, because someone either made so,e mistakes while butchering, or made a mistake labeling the pkg. Either way, you got one beautiful cut of meat!!
Tim
Thanks for the comments!
I think Dustin nailed it, must be from the point.
Here's one, grass fed, the same size, and twice the price: https://grasslandbeef.com/beef-brisket-point
I'll probably cook it Smoke Day if it's going to be just the two of us.
The way I cooked a small piece of flat, from the same store, worked well, so I'll try it on this one too.
I just did a 14lb brisket for my nephews birthday pot luck...Presently you can get some beasts at WalMart here for $3.46/Lb. Usually they have 6+ to choose from and it looks like people buy the smallest ones. I am looking for the biggest one I can squeeze on my WSM 18" This one had some great marbling for the price. The point had schists of fat in it like I have never seen. It was a hit...Nothing like that Wagyu looking piece there...