Maybe try taking a few photos with and without flash at different angles of the old shims, the markings might become more visible?? Either way, seems like .20 is what's most commonly found for the trunnion cap shim thickness on an 80 series. IIRC someone posted up years ago that a change in...
What model are you working on?
Assuming it's an 80 series:
What was the thickness of the original shim and did you replace it with
an identical shim? The shims are marked with their thickness so you shouldn't have to go by feel or guess. If the original shims were damaged better to replace...