Underwriters Laboratories is not a manufacturer; they are a testing and certification company. They test and certify lamps, appliances and other products for safety. You will find their label on nearly every lighting fixture sold in the US. They have a website with a search function but in my experience it won't give you any information from an Issue No.
As far as values go, you will not get that here. Your best bet is sales websites like EBay, Liveauctioneers, Chairish.
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