Simple noob question?

Yes you can pre-trim, but make sure you save the original packaging to prove where the meat came from.

Also, yes, you can wet-age your brisket past the "sell-by" date. I suggest having a spare brisket, just in case your aging process goes awry. <---you'll know when you open and smell it.

No KCBS meat inspector in Georgia should ever ask to see labels. I've heard stories of this from other parts of the country and sanctioning bodies, but since Fred Gould directly or indirectly trained just about every meat inspector in Dixie you won't see it here.

As C K says, go ahead and trim. As long as you don't season in any way and keep your meat on ice you are good to go.

50 days? Ya might want to have another 30-35 day packer on standby. 50 days is a bit more of a push then I'd risk without having another.

My team is my brother and I - I'm in charge of chicken and pork. I always make sure I have my chicken trimmed before I leave the house. I don't mind trimming the pork butts on sight as they go fast.

If I cooked all 4 meats personally, I'd have chicken and briskets trimmed before leaving the house. Ribs - if doing spares, I'd definitely have them trimmed to St. Louis cut. Babys - might depend event to event based on time.

The more trimming you can do at home, the easier it will be for you. It's always easier to do it in your kitchen than it is standing in a parking lot or a field under a pop-up canopy, especially if mother nature doesn't cooperate.