Ok, I talked to CZ and to Keith (the dealer I mentioned in my post, above), and here is the skinny. The flush mag is available, at present, only in the 527 American, and only in .223 Rem chambering.
The new mag is a shorter version of the normal 5-shot mag and is still detachable, and still a single-stack configuration. The capacity, according to Keith is three rounds, but according to the person I talked to at CZ is two rounds. I tend to believe Keith, since he was holding one in his hand while I talked to him on the phone.
The trigger guard is rounded on the front and doesn't have the triangular guide plates on either side of the magazine well.
Another interesting fact I learned: The rifling twist of the Kevlar stocked Varminter version of the .223 Rem cal 527 is 1 in 9", but the twist of all other .223 527's is 1 in 12".