I believe this is a U-923. Here is a detail of the top and bottom. In the cross top, you can see

F.M.LOCKE VICTOR N.Y. xx PAT. MAY '89 MAY 22 '94

There is a small flake off one of the cross tops and a small chip on the inner most skirt. (See photos) There is a glazed over spot on the skirt, perhaps when it touched another insulator. A factory imperfection perhaps 1/2" x 1/4" Since the firing rest was on top, all the inner skirts and pinhole is glazed. See previous photo for more details. Now reduced $10 to $35 plus shipping !! NO! Go Lower! Down to just $25 ... someone must want it!! Help me get this mud out of my house!!!.