I called CSM today and asked them both questions. No choke tubes because thats how they decided to make it, Huh? And the vent rib pictures should be available sometime on the website. My opinion on the choke tubes is if they are available, I want em. I'd love to be able to put in SK, SK for skeet, and then switch to IC,MOD or MOD, Full for sporting clays or hunting. And their answer of because its how they decided to make it doesn't make much sense when the 12's and 20's all have em. How about the option of not having screw in chokes. Thay way you could pay extra to not have the machine work done and you would have whatever fixed chokes you want.