RE: headlight disassembly?
Ithink moderator Mickey did a brief tutorial on how to do this a while ago, but I can't find it right now. The site's search feature currently isn't working very well.
I did exactly what you want to do on my previous car (a 99 Grand Am). I wanted to do the body color thing like the Corvette headlights.
I'll try to remember how I did mine.
With the headlight assembly removed from the car, and the bulbs removed from the assembly, CAREFULLY remove the black rubber weather stripping from the assembly. Try not to rip it.
Now the hard part. You need to separate the clear lens from the rest of the assembly. On the Grand Am, the two sections were held together with silicone. I simply used a utility knife with a brand new blade (the sharper the better) to cut the two sections apart. I haven't done this on my Monte, but a couple people here on the site have. And they mentioned that on the Monte, the two sections are glued together and not siliconed. Moderator Mickey mentioned how he separated his, but I'm not 100% on it. It's been a while. I believe he mentioned that he heated up the headlight assembly in his oven. I forget the temperature and how long though.
If/when you get the sections apart, mask off the areas you don't want painted. Sand the areas you do want painted, and be sure to clean off all the dust. Then paint using several thin coats.
Allow to dry and harden completely. Remove the masking tape, and re-attach the lens to the assembly. When you re-attach the assembly, make absolutely sure there is no leaks or you will get condensation inside the lens. This is where you may want to use silicone.
Put the rubber weather stripping back on, and you're done.
I appologize for not getting more specific, but it's been a while.
I do have a few pics of when I did my Grand Am, but it won't help much with the problem of separating the two sections on the Monte headlights.
Hopefully someone here can be of more help.
2004 Dale Earnhardt Jr Signature Series #544