Federal law for a president might be different from Minnesota state law, which allows the use of a customary pseudonym unless there is an attempt to conceal real identity.
If he has a driver’s license and passport, they likely read James George Janos, as will he soon-to-be-arriving Social Security check.
Not really a big deal, as it is a simple process to make a legal name change. He just never appears to have done it.
Thanks for the info.