I just received the Tailpiece that was taken off the Tarr when converted back to 4-string from the previous 5-string modification. There is an extra smaller hold drilled for the A string that is just under the Brass inlay.
There is a lower brass circle with mother of pearl inlay at the bottom still intact plus an empty cutout from a missing crest at the top plus a center inlay partially filled in. I would love to know what was in there. Always a mystery..