Any chance you have something that states the warranty coverage for them? I was trying to remember what they offered back then, I think it was 1 or 2 years with unlimited mileage. I know I exchanged a few sets for new ones under warranty, despite them being physically damaged from off-road abuse. They were good about that in the early days. But things have changed.
Bilstein offered the million mile warranty, which I also utilized a couple times. But they weren't so easy to work with. You had to buy new replacement units (at full retail price) and ship your old ones to them (at your expense) for testing. You also had to prove you were the original purchaser with the original receipt. If they approved the coverage then they would refund you for the purchase of the replacements. Otherwise not. Once they even wanted pictures of the car. And they always had a bit of an attitude, as if it wasn't possible to actually wear out their shocks...but I did.