I was hoping for a simple answer to OP's question. Never had any luck making much improvement to how the hood on a 2006 115 lawn tractor looked. It is full of swirls, nothing like scratches, but just using a liquid polish does nothing! If I understand what's being said here so far about these "plastic" hoods:
-Could have single stage paint
-Could have paint plus clearcoat
-Could have no paint
So, are those really the choices? And, is it obvious which one you have? The 115 I have worked on does not appear to have any paint.
Here is what the John Deere.com site says about this:
Question: Is there a way to remove scratches from a lawn tractor hood with molded-in color?
Affected Equipment: All Riding Lawn Equipment
Answer: Molded-in colored parts are very difficult to reclaim if scratched or scuffed. A good quality automotive wax can reduce scuffs or scratches. Repeated use on more severe scratches may help. If repeated waxing fails to correct the scratch or scuff, part replacement or repainting may be required.
They mention "repainting". That implies they were painted in the first place?
Looks like a simple answer to the OP's question is not possible.
The fact they say wax can reduce scratches and scuffs makes me disbelieve everything they've written - to correct scratches you have to level the surface. Think of a perfectly flat surface like
A scratch/swirl/etc.... will appear like
so you basically need to level the surface (the 'v' above) to make it even again to reflect light properly (in a nutshell).
A wax doesn't do that - it only protects the surface from oxidization (and other stuff) - a polish levels the surface by removing microscopic layers of it.
Unfortunately I have no idea what they mean by moulded in - is it like a gelcoat finish (e.g., like what's on an rv or boat)? If it is, it can be polished.
If it were me, I'd just take a guess and treat it like a vehicle - in any case, yu'll need to use a buffer because polishing by hand will be a waste of time, unless it is clearcoated and the clearcoat is relatively soft (no idea, never worked on a JD cc before). If it's clearcoat scratches/swirls/etc... should correct with no color transfer to your pads; if it's single stage, your pads should turn green (color transfer). if it's molded plastic, I have no idea.