Nah Grant, you'll be fine.
I used a Scotchbrite handpad to key the end tanks which were polished then gave them a go over with a panel wipe. The core was just given a blow with an airline to remove any dust. I masked the radiator side of the core which is not seen from the front then I gave it a very light dust coat of matt black aerosol. A few more fine coats on the core and it was done. Obviously the end tanks can take a normal coverage of paint.
