Remember how everyone called Vault Boy "Pip-Boy", including the devs, until Leon Boyarsky came and said that he's actually Vault Boy, after which we started using the "correct" name, and even Bethesda eventually adopted it?
Turns out, the canon name of the character in question was actually Vault-Man. The character is not actually named "Vault Boy" in FO1/FO2 (nor named anything else, for that matter), but he is named Vault-Man in the FO1 manual, as noticed by MikaelGrizzly, which would make this the canon name... if not for the fact that everyone, including the guy who created the character and the guy who wrote the manual forgot about it. Pretty funny.
Turns out, the canon name of the character in question was actually Vault-Man. The character is not actually named "Vault Boy" in FO1/FO2 (nor named anything else, for that matter), but he is named Vault-Man in the FO1 manual, as noticed by MikaelGrizzly, which would make this the canon name... if not for the fact that everyone, including the guy who created the character and the guy who wrote the manual forgot about it. Pretty funny.