I rarely ever buy prime anything, Costco ONLY sells PRIME brisket packers where I am and they are like $3.29/lb, so not a good reason not to buy them. However, they do have a ton of fat on them that gets trimmed off. I bet at least 3.5 pounds of a 18 pound packer. I swear, that 2 years ago, their packers didn't have quite as much external fat on them, but it seems about a year ago, they started having more external fat... I suspect that the places that pack them , have started trimming them a lot less before they get into the cryovac bag.
I do agree. the cryovac bag should say if it's PRIME or not, it's not just a external label , at least not on the ones I buy.