David, according to Jim Stubbendieck's book "L.C. Smith Production Records" there were 13 made with extra barrels. In order to find out if yours was one of them, you would have to get a letter.
Having an extra set of barrels made when the gun was ordered, the price of the extra set was half the price of the gun. Sometimes in the higher grades you will see ones with a dissimilar set of barrels to cut down the cost.
Many guns were sent back later to the factory for a second set and many were not recorded.