Other side This side shows the cracks off the two small upper blots before the larger hole is drilled, showing left insulator was manufactured first. I would assume that after the cracks were stopped by drilling holes, and plugged, that the mold might be welded? then refinished and polished, I doubt mold paste alone would fill that crack as well as the insulators surface indicates. I didn't trace the lower drill hole on left because I can't actually see it in entirety in the surface. I'm quite certain it's there, as are other cracks between drill holes not indicated. These are CD 143 Great North (Bob and Doug were right) Westerns ( Check the space after NORTH. These are not NORTHWERSTERNs, They are NORTH WESTERNs) This entirely qualifies this as an embossing error, as the current price guide is written. Would be most interested in seeing other posts with the surface anomalies traced out. I'd do it myself, but it takes a while between finding these babies and they do not appear to be getting cheaper. I for one, would like to see a progression of the demise of this mold in all it's ugly glory. The only way for me to trace out the cracks and "repairs" is to hold it at an angle and use the reflected light. I wasted an hour trying to photograph what I was seeing,. Sharpie was the only way to photograph.(wrote that when first posted under embarrassing errors, cut to the quick, ll this stuff has been well studied and documented by Mark Laukner) Update: got a great response with links to Canadian insulator site, ( seem to have lost email and links, Thanks for the response though)Mark Laukner seems to has done a great deal of work on Canadian glass! (That sentence is my entry for understatement of the year) I being a relatively new collector had only seen his name associated with special issue stuff that doesn't interest me. Anyway his book is downloadable, and it answers questions I didn't know how to ask. I in particular, besides my interest in the mold repairs, and the lineage of the three molds used, always wondered about the many different bases on Can. 143s. His drawings clear it all up pretty well. Check it out! Highly recommend.