The TRD package had different items included in different years.
From Toyota it was known as package code "OF" and in 2000 it came with:
Rear differential lock, 31" x 10.5" tires, front and rear alloy wheels with 15" diameter rims and 7.0" width rims, wheel opening moldings, black overfender wheel arch molding, logo/graphics exterior decoration, TRD badging, heavy duty alternate suspension; excludes: [KX] full color keyed package (Xtracab); includes: [TA] tachometer; requires: [FD] 4-Wheel Demand (4X4 V6)
Note that the suspension is going to be Bilstein on the TRD.
The problem is that Toyota sold a lot of these items as seperate options over the years and a lot of people have certain components with just a TRD sticker added in.
The only way to truly tell if you have the full TRD package is to have a dealer pull up the option list on the VIN of your truck. They can tell you if it came from the factory with that option code. However in 95% of circumstances, if you have an e-locker, you have a TRD package.
If you want to read all the ins and outs of the package and identifying marks, read this: