Chroming is always possible, but it needs to be done by someone who knows what their doing, as with any form of plating it add's a micro layer of material to the item, so if done wrong the piston may fit tighter (if at all) and be prone to seize, theads on the pipe and bleed nipple may become tight,
If all is done correctly make sure you clean the thing well before you put it together as grit used during the polishing process may bugger up the seals,,,,,
If its ally why not have it polished,,,, hugh