In my opinion you would have to buy regular rockers and then have them chromed. Once chromed you would have to weld them in which would discolor the chrome.
Stainless Rocker Mouldings... Concours Parts show them online, no picture, so give them a call and ask questons, I have bought lots of stuff for my 51 from them with good service, I know nothing about the quality or manufacture of these mouldings. just trying to help