I believe this is a Kerr(?) CD 155 on Jim Fursitieri's table was the result of shenanigans of the factory workers setting a penny in the mold, resulting in this imprint on the top of this piece. I think it is a Kerr, and it probably occurred around the time of the flat tops and cobalt swirl/blot monkey business as well. The 14th Annual Allegheny Valley Insulator Show at the VFW Hall in Natrona Heights, PA on Saturday, April 5, 2014.