Hi Walden, I don't know but molds are something we need to explore in more detail, as I'm pretty sure that the same molds were bought by different glasshouses, which could explain why, for instance, we see Bagley State and Libochovice 1880-1884 pieces that appear identical. Some glasshouses seem to have made all their own molds, others bought them in, whilst yet others made some and bought others. I'm going to add a section to the GTS website about moldmakers shortly.