I recently purchased a Scotch Bowl with two makers marks on the bottom. One is a ghost "ERIE" and the other one below it is a scripted Sidney O. There are 2 sizes marked 6 and below it a 4. It looks like its an "ERIE" 6 and a Sidney 4? The O is almost superimposed over the 6. The scripted Sidney almost looks like it was stamped twice. Can anyone tell me what this is? Thanks.