I would really need to see and feel the surface before being able to comment properly.
but in a nutshell, i would say no. its not a suitable surface to apply a wrap too.
will you be able to do it and complete the job? Possibly but it will be short term.
Personally i would not do it.
anything other than a high gloss surface, I would not wrap it.
I see countless wrappers apply wraps over matt primed car parts. I would not do this either.
you mention rough surface. this indicates a tiny uneven surface.
the peaks of the risen areas are levitating the adhesive. so there is not 100% contact with the surface.
being a fibreglass bonnet, it will expand and contract with the heat of the race car. this again will increase the cavity of air behind the vinyl due to the rough surface. basically just promoting a fail.
if the bonnet has typical race car vents or raised areas, again this will lead to a fail.
as i say, i am saying all this blind.
if he wants it regardless of your advice, give him it but outline he has been warned and there is zero come backs to you, if it fails. however, dont give him it any cheaper. the same material and work has to go into the job regardless to what its being used for or the probably outcome of the life it will last.