Does anyone know when G&F cabooses X-65, X-66, or X-67 were covered with steel sheathing? I'd assumed that it was early on, but a picture from August 1957 shows a red X-67 sitting at Augusta with wood sides with white dots along the bottom and the round G&F herald with triangle inside painted in white inside of a green square between the windows on the stove end.

Also, was there ever an X-63? Have photos of 62 & 64 but never a 63?