proper bead blasting, as in glass bead, should not pit the alloy - it will actually start to polish it.
if you are super sensitive regarding the substrate, go with soda blasting.
as to original bronze, there is a thread in this section that gives the paint code, not sure if it was correct or not... but from all the bronze powdercoats i've looked at, im yet to find a match
then again i havent had a set to work with to make a match to either.