Hey Scott,
While clarified by others already, have a read here please:
en.wikipedia.org
View attachment 2787407
There is a "however" with claiming 1951 as the start of the Land Cruiser. The Toyota BJ model started off as the "Jeep BJ" and was later named Land Cruiser, after Jeep started complaining. Per the write up this happened around '53 or '54.
All in all using the 70th anniversary badge on a 2021 Land Cruiser appears legit and it is something Toyota is doing from the factory for the 2021 LC300's.
Have not bought this 70th Anniversary badge yet, warming up to the idea though!