Since when don't guns gain value? Put it to you this way in my cabinet is a Ruger M77R round top 30-06 bolt action rifle. I purchased it in 1979 with scope, sling, flip up scope covers and 2 boxes of shells, all brand new for $212.00 + tax. The rifle has been hunted hard, killed a pile of groundhogs and many deer. The trade in value of the rifle is now in the $400-$500 dollar range, insurance value of over $600+. This is just the average Ruger M77 not a special edition like the TU shotgun you just won.

Use it but keep it maintained. Clean it after every use. As long as you don't do any major damage to it the shotgun will definitely gain value because IT IS A SPECIAL PIECE not just an ordinary Browning semi-auto.