It started life as a "5" chip: IN-SF (pg 166 in Dale's big book.)

When the chips were redyed in England the whole chip was treated and dyed. The intense color masked the design so the central area had to be shaved back to remove the color and expose the design.

Some of the original designs were deep enough that when they were shaved the design still looked good after the re-manufacturing process....

mine didn't fare so well. Now it's coded IN-CI.