This thread from another forum seems to concur that IBP (now known as Tyson Fresh Meats in the retail market-- Sam's is considered wholesale) ribs are enhanced.
I'll second what everybody else has been saying...I've never seen enhanced ribs at Sam's. Be they spares or be they BBacks
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Mark WAR EAGLE!!
Depends on who you ask. Some might tell you that removal of the skirt makes a St. Louis style into a KC style, while others may continue to refer to it as St. L. Still others may totally reverse the definitions.
From what I saw of them at Sam's the other day, they will still require some trimming. Check out the Rib Selection & Preparation Topic in the Cooking section-- there are some photos and even a video that show popular trimming techniques.