In some games, yes. In other games, no.
There is a distinct difference between a standard bright white plastic pop bumper body and one reinforced with carbon fibers. The ones with carbon fibers are much more common in early Williams games like Firepower and Barracora, but I do see them on 90's machines from time to time like Getaway and Funhouse (especially ones with DP play fields).
They are also thicker, much stronger, and not as brittle. They appear much darker and are more transparent than the shiny white ones. I will attempt to track down one of each style/type in my parts pile as an example to try and show the differences when smashing each with a hammer.
The pinball manufacturers sourced parts from different companies back in the day... I suspect that when they ran out of something, they just used whatever they could locate quickly on the assembly lines back in 90's pinball heyday. This could account for the different materials/plastics being used for the same Bally/Williams part #'s. The grayish carbon fiber ones are just an oddity that I prefer.