Ultimately, a name is a name, whether it be the one on your birth certificate, marriage certificate, or the nickname on a shirt. I am known as slumpy by hundreds of people [even my parents], most of whom know my real name so for me it's no big problem. There are just as likely to be as many duplicate slumpys as there are duplicates of my own real name.
Signed
Horatio Catburglar O'Shaunessy III [aka slumpy]