The text says:
“at columbia (undergrad)
Forget the Great Depression. The Great Decline can be traced to enrollment into Columbia University. Out is the afro and devil-may-care carriage. In is seriousness and an un-ironic leather Members Only jacket.”
Which suggests a figure of speech maybe and not that the jacket was some kind of uniform, surely?
Since it's such a consistent theme I was thinking that if the make and model was known then it would narrow down when it was available.
For instance...he couldn't be wearing it in 1982 if it didn't come out till 1983. {;^)