Also, I noticed that what has become today's Metropolitaine began from then Hwy 2 following what is now A-520 to get to what is now A-40. Does anybody know, was Metropolitaine first an at-grade divided highway that was later upgraded to an expressway standard during the Autoroute era? It would seem that way.
Yes, indeed. Autoroute Côte-de-Liesse and autoroute Métropolitaine follow old rural roads. You can even observe
some remnants of it.
From west to east, boulevard Métropolitain replaced:
-Chemin de la Côte-de-Liesse (route 2/late A-20 to Chemin Sainte-Croix)
-Chemin Vervais (Ste-Croix to rue Saint-Hubert)
-a road parallel to Chemin de la Côte-Saint-Michel/late rue Jarry Est (St-Hubert to Longue-Pointe limits/late boulevard Langelier)
-Chemin de la Côte-Saint-Léonard (Longue-Pointe limits to Island Boulevard/late boulevard Henri-Bourassa)
These roads were twinned in the 50's, with a large median to allow the construction of a freeway. The highway then bore number 2B. Traffic used the service roads. The first limited-access section to open was the elevated section, in 1959, between actual A-520 and Pie-IX boulevard. Interchanges were gradually built connecting the service roads. A-520 had its express lanes opened in 1966, A-40 between Pie-IX and boulevard du Roi-René in 1969 and Roi-René to Henri-Bourassa in 1971. (Meanwhile, the Transcanadienne towards Vaudreuil opened in 1963, service roads alternating with freeway lanes)

Boulevard Métropolitain (A-40), approaching boulevard Henri-Bourassa, looking east.
Picture by Gabor Szilasi (1970), Archives Nationales du Québec.
Late
Google Street View.

Boulevard Métropolitain (A-40), east of boulevard du Roi-René, looking east.
Picture by Henri Rémillard (1970), Archives Nationales du Québec
Late
Google Street View.

Boulevard Métropolitain (A-40), east of boulevard du Roi-René, looking west.
Picture by Henri Rémillard (1970), Archives Nationales du Québec
Late
Google Street View.

End of Boulevard Métropolitain/Beginning of Autoroute de la Rive-Nord (now Félix-Leclerc) (A-40), near boulevard Henri-Bourassa, looking east.
Picture by Henri Rémillard (1970), Archives Nationales du Québec.
Late
Google Street View.