30+ years later...it's kinda difficult to denote with badge changes, and the fact you could order anything you wanted at any trim package. In theory, you could order a custom level truck better trimmed than a Lariat. That said, there were standard options available that could denote the classification, I just don't know what they were...but there are some folks here that do have the brochures and could tell ya.
Edit...how's that for an answer that doesn't tell you a damn thing.