Ol' boy can be used in reference to anybody previously metioned in a conversation.
It can also be used in reference to a girl's boyfriend.
"Ol' boy is trippin'."
"Say girl, how's ol' boy doin'?"
A lad that has been 'on tour' to become and ol' boy.
On tour is the journey through life, where a man will learn many a thing. He begins as a simple child, then growing through adolesence into an age also known as 'Ladhood' which is infamous for it's relation to the drinking culture.
To become an ol' boy is a prestigious moment in a mans life, it is a declaration; that the man in particular holding this title is one to be respected - for he is all wise in life, and a role model to all currently in the stage of Ladhood.
"Whats that prick on about?"
"I dunno, but I would listen to what he's saying, Les Rouse is an ol' boy."
"Why should I listen to you dad?!?"
"Because son, i'm an Ol' boy. I've lived life."
a term used for calling a random person
Olboy! Come here real quick.