Speaking of that, Chuck did you get your conversion done?
Sand or grit blasting is good for the pedalbox and associated stuff but I would refrain from doing a master cylinder. Glass beads under low pressure will provide a nice finish but consider the fact that you will be removing the original zinc finish if you blast an early m/c, or clutch m/c. And there is the danger of the grit getting inside and making trash of your new seals, so be sure that it is super clean before you reassemble is you go the blasting route. Oh, and don't blast the inside bore!