Black antique paint on gold plated surfaces before e-coating

We're a fashion jewelry manufacturer in China.  One of our customers require antique painting on letters or textures on gold plated surfaces of casting before e-coating.

Our concern is that the e-coating bath will get any unbalances or any contamination when we put antique painted plated metal components in it for e-coating.  We might throw it away wasting money.

Please kindly advise if it's feasible for us to do antique painting before e-coating.

any of your comments will be very appreciated....

Collins Cho