Mazda RX7 turbo calipers

[Shadowbug]

anyone know much about these calipers?

I'm wanting to polish them up but I had a question, the little nub below where MAZDA is cast into them can this be ground off?

good sence would tell me that this might be where brakefluid travels connecting the two pistons on that side of the caliper, but if it is not, I'd just as soon grind it off for a cleaner look.