Lionel has a Catalog Archive back to 2000, but I don't see the JLC Challenger in 2000 to 2002.
Good morning Gunrunner John, just wishing you and your family, also Bruk, your model engineer that rebuilt this fantastic Challenger, a very Happy New Year. It’s projects like this that make our hobby so much more fun, amazing ways to make our locomotives/diesels operate with so much more realism. Yes, we love those post war favorites, but these new giant locomotives, with all the bells and whistles have taken our hobby to a much higher playground, a model railroading utopia. Your thread proves that if we think it, it might become a reality. Thank you for your contributions to our hobby, via the OGR Forum, a great place to be during this pandemic, a secret psychologist. Happy Railroading Everyone, 2021 will be a truly great year.
Well, the bright spot is it's hard to imagine 2021 being worse than 2020, so I am hoping you are right Larry! 
Happy New Year to all!
Hi GUYZ,
The JLC Challenger was in a series of brochures that Lionel put out. I think the Challenger might have bee the first or one of the first brochures sent.
Laz57, Thank you for the information and I think your correct. I Suppose it was a special run and was a BTO piece. Happy Railroading
This will confirm that the brochure for the JLC Challenger was distributed in 2000 and actually referred to three (3) product numbers, two of which were 3-rail versions and the other for a two-rail version. The UP Challenger #3985 with Coal Tender (which GRJ has) is 3-rail (6-28064), the other 3-rail is UP Greyhound Challenger #3977 with Oil Tender (6-28099), and the 2-rail version - for which no cab number was provided - is (6-28090); all of which had a MSRP of $1,799.95.
I have the Greyhound #3977 also, but it doesn't have any "deluxe" Legacy upgrades. 
Now that you mention Lionel brochures, that rings a bell, I actually had one of those Challengers 6-28064 and sold it to a friend, (I kept upgrading from TMCC to Legacy steamers) Wow, and I probably have the Lionel brochure packed with other catalogs of the 2000 era. Thank you very much. I am really amazed at the work Bruk performed on this beautiful locomotive, I would have been a player to, it’s really nice. Happy Railroading Everyone.
