So I purchased a california special bumper for the mustang several months ago. This project has been on hold due painting the house and other projects. Finally started working on this a few weeks ago. Turns out painting is not my forte, but thought I'd give this a try to see what I could do. I purchased all of the paints from the local NAPA store. My biggest concern was the paint color matching. As it turns out, it's spot on.
My first attempt was pretty weak. I didn't hold the paint gun close enough to the bumper and ended up w/ a really bad golf ball dimpled effect on the entire bumper. Hello 600 grit sandpaper. That took me a few days to get it back down to smooth surface, but I did manage. From there another coat of primer, base and clear. Lowered the air pressure and closer to the bumper. Much better, but still not great. Hello 2000 grit sand paper. After many hours of sanding and buffing, I think it came out ok. I can tell you now it's strictly a "5 footer" paint job, but it does match the patina of the car over all, so I'm good w/ that.
So here a few shots of my handy work....
Up on jack stands getting ready for the swap.

here's the B sans bumper. Amazing how easy this is to take off.

here's a pic of the 2 bumpers side by side with the CS bumper still a work in progress. I wanted to see if the paint was matching. You can also see the subtle differences between the two.

And the final product. Not too shabby for a home grown effort. Would I do this again? No, not worth the time and effort I've put into this, but I did learn a lot and it was a good experience.

Now I have the "proper" front bumper on my Bullitt. Very happy w/ the outcome and it sets the car off nicely.