One ex-gf at one time had had a black bf. Now, bf said to her, concerning a mutual friend “I’ll go by Old Boy’s house before coming over.”
Many years later, a black co-worker said to me “I asked ‘Old Boy’ to come in on his day off.” I knew of whom he spoke, of course, but the reference hit a note.
Later on, he told me that he had asked ‘Old Girl’ to do something. I knew of whom he spoke, but the Old somethingorother rang a bell.
So, in the black community, who is ‘Old Boy’ or where did the name originate?
Not really an answer, but another point of ref: I come from the hard-coal regions of NE PA. We say, “Our lad”, as in “Our lad over there is buying a round.”. Also say “Our lady” where appropriate.
This is a very common expression here in Mississippi. I’ve heard it mostly from whites though.
ETA: Also, it’s more common among the over-35 crowd. Younger people say ‘dude’. “I saw dude walking on the tracks today”. “Then dude brought me my latte”.