I would assume they at least run a patch, but they probably do a thorough cleaning of the action and test fire. You should be able to tell if there is copper wash in the barrel, but it doesn't really matter as copper wash does no harm.
A friend who was, at that time, one of the top shooters at Camp Perry, swore by using Gleem toothpaste on a bronze brush to remove the copper. Fortunately, he retired before P&G took Gleem off the market.
