Went to replace tie rod ends on 2000 SL. It appears either the factory ends were installed without a jam nut, or the nut has completely rusted onto the end. So I guess my question is was the OEM part not have a separate jam nut?

 

There is indeed a jam nut. The attached screenshot is from a YouTube video by Richpin06a and shows the tie rod end removed with the jam nut still present.

I looked on rockauto.com and none of the replacement tie rod end parts available seem to come with a new jam nut.

Given that it's 20 years old and has probably never been replaced, I would not at all be surprised if it has rusted into partial Oblivion.