The fretwork is ebonized. It was my first attempt at ebonizing. Truly amazing how you can dip a piece in, pull it out unchanged and then watch it darken in minutes.
Here is the piece before and after ebonizing. I added a simple rounded bead board-like frame, which I think adds depth and sets it off nicely. I included the backing piece cut to size for Bruce, but agreed with him that it was too light to match the case. Better too light than too dark.