I think it's a thing in mainly in the Far East were certain numbers carry more significance. I think it is 6, but it might be 8 - not sure.
People with a low number will always claim it's worth more - but they would, wouldn't they.
I had a number 16 which is my birth date, which was nice - still sold the Watch though.
I think if you are lucky and get a number that has significance to you then good, but probably means nothing to anyone else. Bit like personalised number plates really.