I pinged Bowser by email a while back - asking for 3390 and 3391 in their GMD Canadian-line of SD40-2 locomotives, both in MQT and HESR sublettering. The response I got back from Lee English seemed positive - perhaps in the third run, now in planning stages. Hopefully Intermountain's move won't derail the possibility of a more-correct GMD unit for these ex-CP engines.
I would much rather wait for the Bowser versions, which will actually be correct, over the Intermountain version. Intermountain's "GMD SD40-2" is just their EMD SD40-2 model with different steps a cab mounted bell. They have never tooled the correct nose, hood or pilot variations correct for GMD units and likely never will.