You could look at your door tag in the drivers side and look at the AX code. This will be letter or a few letter and is an identifier for what axle it has. Looking on line at images of the deluxe coupe they all have the duel exhaust. Considering you have the deluxe coupe and the bumper has cutouts for the duels I would venture to guess that they connect to a stock H pipe and came as an option when the car was ordered.
The sport package may or may not have included such things as steeper rear gear ratio , sport exhaust with duels, premium sound , sport wheel package such as where the base model had 15s or 16s the deluxe and premium may have had 17" inch rims. There is likely other differences such as body packages ie bumpers , side skirts, and possibly even slight variances in the hood scoop . I don't believe there were any engine differences as all the 3.8l v6 engines of that year were 193 hp. The torque ratings may be different if they had a steeper gear set , but like I said they may or may not have had options for that.
Hey I have a question regarding my car. It's got cut outs for dual exhaust in the bumper. I cleaned the tips today and removed all the rust, and ended up getting surprised by what appeared to be true dual exhausts. I didn't investigate much because I assumed it was never a true dual (and the internet says it can't be stock) but there's cutouts in the bumper for it, there's no Y pipe, each exhaust tip went straight back to another muffle and then beyond that I'm really not sure since it was getting dark out. What's your though on the matter?