I could not tell if the woman in the exchange pronounced Do or dropped it when she asked the man about his name; I could not hear the word Do at all. For all I know, whoever transcribed the conversation might have added Do. Then it came to mind whether there is any difference in tone/stress between:
Good, strong name. Your friends call you John or Jack?*
The sentence is part of the exchange below from Vertigo 1958.
Thank you But I don't know you, and you don't know me
My name is Madeleine Elster
My name's John Ferguson
Oh, John, mostly
Bold Do was replaced by [Do] between brackets to help improve readability. No intention of adding stress to the sentence.