In 2003 there was an Amazon exclusive pre-order bonus to get an Elle Woods celebrity NPC download for The Sims: Superstar that nobody in the Sims community has been able to find. The few Sims 1 archive websites I have seen do not have it, or are looking for it.
It might be worth messaging sellers on eBay to see if they preordered the DLC? A lot of results come up when you search for it, so it might be a bit time-consuming. I noticed that in the Amazon listing, the disc is in a CD jewel case rather than a DVD keep case (and it doesn't have cardboard packaging like some of the other Sims expansion listings), so maybe that narrows it down slightly?