Didn't they do the same after the fallback of 1975? Appoint elders early when old timers realised the gig was up?
There were instances of that when the "elder arrangement" was first implemented. Amongst the first group of elders to ever be appointed in our district (which happened during September-October 1972), there was one who was only 19, and at least one other who had attained the mature age of 21!
As far as I can recall, though, these were "one-off" situations. By the mid to late 1970s, they made a particular point of only appointing those who were in their late-20s or older. (And used to look down their noses at the LDS "Elders", most of whom were barely in their twenties).