If it's the one with the white inner bezel, and black dial, it looks to be a parts bin special with a fake dial.

The hour and minute hands don't look like Montreal, nor is the 30 minute sub-register hand correct, most of the black dial Montreals I can find pictures of have a white border around the date window, the luminous hour markers don't look like Montreal, and the black dials didn't have the yellow segments in the 30 minute register. In fact, the dial looks very much like the ones in the OTD Gallery of Fakes.

I haven't looked through all the catalogs to see if Heuer ever offered that dial/bezel/case combo but it looks a tad suspicious to me.

Bruce B