I think JSB may have changed their packaging a little. They used to have Predator on the tin and polymag was not mentioned, and there was a big green circle near the size of the OD of the label. The new .177 tins I just bought look a little different. Now they say Predator Polymag and the label is black, white, and red. No green circle, and on the bottom of the tin you can see a reference to JSB.
Rest assured, they are both the same pellet, just a modification to the predator name. So we can call them predators, polymags, predator polymags, or my favorite...polymaggits.