I need some help from some guys who know more about these things than me. I'm looking at an early contender (Lion on the frame) coming up on an auction this weekend that has three barrels. I can only view pics on the auction site, but it appears that one barrel is a rimfire, one is .410/45 barrel, but the other is unknown (auctioneer is not answering his phone). My question is, what centerfire calibers came with a vent rib but had adjustable sights? That is all I can tell from the picture.

Thank you in advance--Pythonhunter