Moog B-Joints will not work with DJM C-Arms?!

A shop is trying to tell me this (length/angle?). Just wondering if anyone else knows about this and what I can do? I don't believe DJM sells the balljoints seperately which is included with their 2" Drop Arms for the Gen III Dakotas. Does anyone know of the model I should purchase and/or what DJM is using?