Sounds like that Grand Am museum is comin' along!
LJ vs SJ...most would agree that the L sorta leans towards Luxury, while the S leans towards Sport, but in reality both can be equipped almost identically via that 'ol OPTIONS list. The SJ MSRP was about $200 higher.
The following are features that came std on the SJ, but were options on the LJ... the 4 bbl carb, the rally gauges (but not the tach), the lamp group, bucket seats and console, custom sport steering wheel, Rally II or aluminum wheels...all available in the LJ.
Conversely the LJ came equipped with the Luxury cushion steering wheel.
I've seen alot of both over the years. One generalization I'll make is most SJ's are more likely to have a tach, a custom sport wheel, and fancy wheels, while LJ's are more likely to have the padded landau roof treatment, power seats windows and locks, and 60/40 split "loose-pillow" velour seats.