Not really -- except for a small portion of 138 (perhaps 20kms between Quebec City and Neuville) both routes are right next to the river between Quebec City and Montreal, except a portion between Trois-Rivières and Sorel (132)/Berthierville (138) where both are away from it.

I have done both routes many times. Between Montreal and Trois-Rivières neither side is anything special, but between TR and QC both sides are worth it. I think the view is a bit more scenic on the 132 but I've often heard others claim otherwise. You may be confusing 132 vs 138 downriver from Quebec City, where 132 is still right on the river while 138 is mostly away from it (but still gorgeous as it is in Charlevoix).

If you have some time, you can get the best of both worlds by going on 40 from Mtl to T-R (highway hugs the river at Lac St-Pierre.. marshes and some nice bird viewing spots along the way), then cross the bridge in T-R and take the 132 to QC. That way you get to cross the river again when you arrive in Quebec City, while the inland approach on 40/138 in the last few kms is rather nondescript.