I’ve been trying to find a replacement knob for a 30-year old washing machine. Searching the appliance parts web sites, they all seem to be able to locate the part --actaully a replacement – if I simply enter the manufacturer’s part number (MPN). (Fortunately my wife saves EVERYTHING so we still had the parts list book). But the sites never asked who the manufacturer is, which leads me to believe that somewhere there’s an international MPN czar, parceling out number to various manufacturers. I’m just amazed at the possibilities – my washing machine parts book has over 100 parts listed, can’t imagine what the entire universe of MPNs would encompass. How exactly do the manufacturers avoid duplicating others’ numbers?
The manufacturers I used to work with (consumer electronics) had specific part numbering systems. Example:
Sony: #-###-###-##
Matsushita: abcd-#####-a
Sharp: ########-abcd
Pioneer: abc-####
Kenwood: a##-####-##
Aiwa: ##########
And so on. Sometimes there’s a deviation but in general the manufacturers pick a numbering system and follow it pretty closely. Some manufacturers use the other’s part numbers, just adding an extra digit to make it their own. For example:
Sony optical laser pickup KSS-210A part number = 8-848-127-11
Aiwa optical laser pickup KSS-210A part number = 9884812711
So if you called me and said you needed a laser pickup with part number 8-848-127-11, I would know right away that it’s the KSS-210 pickup and you’re working on a Sony product. Ask me for part number 9884812711 and I’ll hand you the same exact part but I’ll also know that you’re working on an Aiwa piece of crap (sorry), or at least working out of an Aiwa service manual.
Hmm… I always thouth National Stock Numbers were universal but part number weren’t (in case your wondering a National Stock Number foolws this format: 000-00-000-0000).
But a lot of things don’t have NSN’s, because they’re from foreign companies (or domestic) that don’t deal with the federal government.
I used to know the NSN for Budweiser Beer, but being a class 6 (IIRC) commodity, we couldn’t order it. 
I used to have to cross reference other manufacturer’s part numbers to ours. I have often wished that there was some “standard” way of formatting them, as some manufacturers seem to delight in making part numbers as complicated as possible. National Stock Numbers always seemed to me to a good format to follow.