I don't think ISO have any requirement or recommendation on that level. The level they are on is more something like "It should be able to track.".
Your suggested naming standard would not be enough for a larger company.
Lets say a big automotive company like any of Volkswagen, Ford, Caterpillar, Volvo or similar. They would have many different buyers responsible for their commodity and since they are buying a from many big vendors there are companies that overlap more than one commodity. Therefore it is not uncommon to have more than one quotation to a vendor same day, I would think. So if you can have this as a (future) possibility or similar, I would not suggest only having date. Rather an incremental number or something where you can track the which document it is.
Also, I agree with Tiago regarding externals not being interested in what kind of standard you will have, only that you can track documents.
I recommend you to call a big company and ask what kind of naming standards they might have if you cant find your own standard.