Yes.  It can screw on in place of the platen, and will support the tank bag at least as well as the BMA plastic platen.  However, there are a few drawbacks.  First, it is metal, and with the tankbag removed, it can be forced into contact with your tank, just like the plastic one.  Being metal, it would scratch the paint if that happened.  Second drawback is that your gadgets would stay on the bike when you remove the tankbag, so there is a reduction in convenient security.