Just an update on WMS backglass. Was looking promising for Bally/Williams glass, but the deal hit the skids for what is expected. Unless Rick changes his mind, I will focus on Classic Stern & Gottlieb glass.
Do you mean Bally Williams translites ? You should have no problems reproducing BALLY or Williams backglasses prior to 1983 ish. From what I understand, no one owns the rights to these machines and the only issue you will have will be with third party licenses. You could easily do a run of Supersonic or Gorgar (as an example). You would not need to ask permission, as no one holds these right - in fact, I don't think they exist (the "rights").