I'm looking to take the M&P slide from the original black to OD Green.  I'm going to use Krylon to make sure I like it, then may Duracoat later.  However, I'm wondering if anybody has sprayed a pistol slide, because I'm wondering what do do about the sights.  They don't exactly come off very easily, and I don't want my sights getting all fouled up.  If anybody has any suggestions, please let me know.  

Use blue painter's tape and tape them off.

Yeah, that's what I was thinking...guess I'll just have to cut some custom strips and be really steady.  I don't want to get paint on them, but I also don't want to have fouled up paint lines because I put on too much tape.

+1!

Painters tape works great. I use it on most of my paint jobs too.