I just got an 1100 SG at Cabelas. It has 2 VR barrels, neither original. It is 2 3/4 12GA barrels are 30"full, and 25" imp cyl. I will get a new o-ring. Should I change the 2 metal piston rings as well? It was dry inside but in great shape. I believe it is about 40years old. Should I get a change choke barrel and sell off these present two? I intend to learn trap shooting. I have been a NRA bullseye and smallbore prone shooter for years, and years, and years... Also deer hunter with Remington 721 many times.