Where all models with leather seats heated seats?

No, heated seats were an additional option.

I have been working for Toyota and Lexus since 1997. The 4 Runner Limited is a terrific vehicle. Usually when Toyota calls something Limited, it will include as part of their optional equipment leather, and sunroof. Some people complained that leather was cold in the morning and so there was a request for heated front seats. It was not standard. I do think though on the 2005, it was fairly commonplace.