If you don't want to risk removing them, I'd mask the caps with tape, blast it, then clean up arpund the caps by hand. Once your ready to paint, go to your local hobby shop, one that sells plastic models. There is a company called Microscale that sells a liquid masking solution called Micro Mask. You paint it on with a brush, let dry, paint your item, then peel the mask off. It's great for masking intricate items like head badges. Sounds like it may allso do the trick for you.

Yes, the Kawamura frames do typically start with a K or C. I've seen some exceptions. It can be frustating.