Exactly as He posted - I think…
Now that I have received a couple of the new couplers (p/n G880X-00R01) I can give ya a much better look at them. First off, they mount similar to the Spectrum couplers with one minor difference. On the top of the draft box cover there are two ‘dimples’ that I have no idea what they are for. 
The as delivered coupler looks like this: 
The coupler and draft box separated: 
… the coupler and draw bar separated: 
And finally a comparasion of the G880X-00R01 coupler mounted to the same surface as a straight shank Spectrum coupler. 
My photo is not the best, but the G880X-00R01 is a bit lower (by about 1/3 of the coupler face) than the Spectrum. I suppose with cutting / shimming they could be made to match. Now if Bachmann would only make the draft box and draw bar available without the coupler I could use up all the busted couplers I have in a box. Bob C.