I thought 88-94 were of the same generation, as they all have v6s as an option. No? Plus the pre88s look funny. This wikipedia entry says that only 89s and up had v6s too...
No, the trucks are listed by body style, not engine. The '88 was the worst year of V6, and can be replaced with a newer V6 if it's shot. I personally like the '84-'88 body style, but they're so prone to rust!