The paint is more or less the same stuff that cars "used" to use. Single stage, though instead of base/clear. Similar to cars, if a coat of wax isn't put on them, the UV isn't reflected away from it, and in time it WILL fade. If it were base/clear and no wax was used, the clear just peels. Just like cars. Kubota paints them but they don't wax them. I'd suggest removing the loader if equipped (takes like 45 seconds if you work quick), then wash it down real good & apply a good wax to the painted surfaces. Wheels obviously would be exempt, wax won't last at all on wheels. But hood & fenders, it will help immensely in making the finish last a long time. JD has the same issues with their plastic hoods fading but wax doesn't seem to help those. You just replace the whole hood with another plastic one which will be nice & new, and won't "match" the side panels and fenders that have some sun fade. I've successfully used diesel fuel on the faded molded-in-color green hoods to "bring them back"-and that seems to work ok. For reference, on some of the old T series mowers, they were bad famous for fade; the one I have was mostly pink when I got it. A wool pad on a drill with some polishing compound brings them back to basically looking brand new again. I have a T1460 that I picked up a few weeks back for my girlfriend's sister....it was nasty, but ran and drove excellent. I completely disassembled it, 100% down to a frame, repaired the little things and then just gave it a good cleanup. It literally looks and drives like a brand new mower, exactly what she needs for her high-end subdivision's "standards"....which will beat the snot out of the old Crapsman LT2000 that she's had for a number of years. Besides, the 40" Kubota deck will mow circles around the LT2000's 42". That Crapsman deck is JUNK! She can't even engage blades without breaking one of the aluminum spindles....
I love watching this site, because I, too, learn from it. Some issues I see like this one are isolated but it goes into the "old hard drive" (aka chrome dome) for later reference should someone show up with a similar complaint.