The only way is to refresh the display with a different image and see if it has ghosting and/or burn-in!
Or wait, what if ... just what if they had like 2 identical set and after 12 years, one of them is refreshed, and hence you know that it does not have ghosting and/or image burn-in, while the one that is not refreshed shows that it retains its contents perpetually.
Man, they should get me to device demo plans and Proof-Of-Concepts.