I can only speak to FBA. Below is stolen from their webpage on rules. I suspect that it can't be that incredibly different than other sanctioning bodies.
"All meats must be USDA or state DA inspected and passed. No pre-seasoning, injecting, marinating or cooking of any entry is permitted until after inspection by the Official Meat Inspector as appointed by the FBA Representative or the contest organizer. Meat inspection begins at noon on the day prior to the contest. All meat must be maintained at a maximum temperature of 40 degrees F prior to inspection. Prior to cooking, all meat that is resting in preparation for cooking must be covered at all times. All meats must be cooked to a minimum internal temperature of 145 degrees F. After cooking all meat must be maintained at a minimum temperature of 140 degrees F in a covered container until turned in for judging. All contest meat, once inspected, may not leave the cook team's site until turn in."
You can pre-trim the meat and put it in Zip-Lock bags. Just be sure to put the original tag that has the inspection, date, description, etc in the bag with it.
They will want to physically see the meat in the bag and I usually put a self-standing thermometer on top that shows/proves that the meat is in an environment that is below 40. I also keep the receipt from when I purchased the meat on hand so that the prices on the receipt match the prices on the labels in with the meat. That way I can show when and where I bought it. I've never had an issue with an inspector.
Russ