Depends on what gets replaced.
Carbon Front fender on the RIIIR is an 11lb reduction.
Carbon Front fender on my Z H2 was a 0.5lb gain.
The 2.3 rockets had a ton of unnecessary metal parts that were easy to swap for CF parts and shave weight. The 2g is likely not in the same situation, and on most sport bikes CF is a weight gain.
There are other considerations, like, paint wear. OEM paint is largely crap these days and easy to scratch with minimal clear coat thickness for paint correction. CF parts don't have that issue.
Even with autoclave formed CF parts, the part should be heavier than the injection molded counterpart, by definition. So as a general rule, if it's plastic is purely aesthetic or wear resistance to replace with CF.
Mufasa weighed ~680lbs fully fueled in its final form and a large part of the reduction was CF F/R fairings, side covers, brackets, etc.