all pieces and parts of primates, birds, pigs and bovines must be inspected at a usda certified facility. They will be shipped to one of these agents and a usda rep will visit, inspect and if there are no issues, release the shipment.
OP did say they needed to be re dipped which is unusual, maybe just incorrect terminology.
This is true around the world-Mexico, Africa, Sweden or wherever. Primates, pigs, birds and bovines get cleared by a usda agent before they are released to the owner.
The owner can then take them elsewhere for final work to be accomplished.
I would think coppermiths explained that unless there is a problem beyond the standard.
I have heard that finished taxidermy is sometimes questioned if stains or bugs/bug skins etc are present but have never seen it firsthand.
Hope that helps and please feel free to correct/educate me if you get a better answer in your experience.