Parkerizing is surface treatment rather than a coating or plating and is easily removed with little or no impact or dimensional changes to the metal. We generally prepare parkerized parts for metal finishing with our standard sand/bead blast process. So, to answer your question, parkerizing can be removed and any metal finish, coating or plating (including nickel) can be applied to the firearm.
The Robar Companies
Offering premium firearm finishes, custom gunsmithing and polymer pistol frame reductions & modifications since 1986.