No.
However when a rider increases his muscle mass, he will probably increase his power output. For some reason, cobbled classics riders are heavy and we don't see 60 kg ( or less) riders winning PR. Just like in track, sprinters have way bigger quads than "endurance sprinters" like Philipsen, Merlier, etc and this is clearly to improve his absolute watts
The big error here is treating neuromuscular power the same as aerobic power. Neuromuscular is limited by energy that can be stored into the muscles directly, whereas aerobic power is limited to a degree by the cardiovascular system, unlike neuromuscular power.
To my knowledge these processes mostly work with concentration equilibria, so you probably can squeeze a bit more power out of being a bit more muscular, but this is unlikely to be a linear relationship.
Adding muscle would also partially offset itself by getting bigger and thus less aerodynamic. There's a pretty good reason Evenepoel is the best ITTer this decade and it's not because he's a huge dude.
IMO the whole Roubaix and weight debate tends to just get cause and effect wrong. There's no climbs in Roubaix, which means they don't benefit at all from their qualities, and they're not gonna win a sprint or stay away solo. So they just don't target that race.
On the opposite end, Roubaix is the one race that should be the primary target for any rider that's big and not super explosive, so they all target it.