If you're only painting the visible parts, then you should be fine. I'd recommend taping off the spring area and leaving that as is. I paint my weapons using Duracoat. You'll want to use some crc brakleen or similar solvent degreaser to remove all traces of oil or lubricants, then rough up the surfaces with some fine grade sandpaper to ensure a good bond with the paint. If using Duracoat, plan on many many light coats. You should still see the black coming through after the first several coats if you're applying light enough. The objective is to let each coat dry before applying the next, which if done correctly is about 20 minutes. I usually take 6 or 8 hours to paint a firearm, only putting it back together a week after it's painted, then only firing it again a month after it was initially painted in order to let it fully cure. Take your time and be patient if you want it to be perfect.
Also, if you do need to remove duracoat, I recommend Naval Jelly made by loctite. I put on too much my first firearm and found that nothing seemed to remove the duracoat. Something I appreciate now, but at that time... didn't. The naval jelly stayed on the slide of my firearm for 6 hours before I was able to remove the duracoat with a brillopad. I had checked every half hour and just about gave up. I wouldn't recommend using naval jelly on plastics or polymer materials.
On a side note, I also painted my hand. It stayed bright blue for about 3 weeks. Very annoying to have to explain that to ppl every day. I wear gloves now and I suggest you do as well.
Take your time, go slow and hopefully any mistakes you make will be small ones.