try it against a set of bodyshop samples, easier to get a mint 2nd hand focus bonnet and have it painted but a bodyshop, cheaper if you get it in when they are doing something else that colour
you wont be taking bonnest to a body shop to see or fitting them to your car but you could hole them nr i guess eithe rway colour match is important but difficult

chances are your car was in a crash and repaired with new parts but they wernt sealed when painted, a basic new panel will rot very quick when its laid with paint but not inside and rots from the inside out just like a KA filler cap