@Walter Hinteler,
Today in the USA, it almost impossible to tell a Jewish person from a Christian,at least by their last name.
For example, if a Jewish couple gives their son a first name of "Kelly" would you think the boy was Irish Catholic if the parents never mentioned either their ethnicity or religion? Or would you think that the child was Jewish?
And what about converts either through ritual or marriage , to Judaism. What does their last names of Lee, Lung, Loo, Maloney, Howe, tell you about their past/present religion?
Nothing...
Today, Americans are such a mixture, who really knows what anyone really is?