I have the A1 from them.
I provided them the Dummy phone to make cases for the TP.
That aside, what they are telling you is correct, you need room for the phone to pivot on to be removable. If you want the case tighter, you need a hole in the bottom to push the phone straight up and out.
So yes, I believe them, they make the D1 for several other phones, and they do have a Dummy CDMA TP to model from thanks to me!
:P