The trouble is that so many of the things we collect were not sold as collectables: they were just ornaments or things to use and they probably had a label at point of sale. You can rest assured that all the modern "collectables" that fill the pages of magazines like Collect it (no offence to the magazine, the manufacturers or the collectors) are well labelled. Even many modern glass workers don't sign or mark many of their more ordinary ranges (unless you ask) because they just making things to enjoy, not things to collect