Quoted from ForceFlow:Read what Coyote posted again. This was a manufacturing defect in a run of reproduction playfields. It's not worth any more than a properly colored playfield--it's probably worth considerably less.
When CPR ran the Power playfields repros, they made a limited edition run (I think of 10) of these playfields that have silver rings instead of red. Despite the photo, I believe the silver is kind of shiny, not a flat gray. It was a special spot color for this edition.