I just refitted most of the steering and suspension hardware in my TA22. The rear dampers were Toyota (Tokico) OEM parts.
Presuming that...
A) the original dampers would've lasted at least 10 years, and
B) that nobody in their right mind buys factory OEM dampers for ten-year-old plus cars
...then I conclude that the dampers were still the factory original items. Working on a presumed 20,000km/yr, those dampers were over 600,000km old. Yes, they were rooted.