I believe it is still possible. The time course for development of AVN is often unpredictable.
Time until AVN is visible by MRI
I had an MRI about 3 and a half months following a posterior hip dislocation. At that time there was no sign of AVN. There were signs of hip capsule stretching, but everything else was fine. Since this time period, and since I’ve begun returning to physical activites, I’ve noticed an increased amount of pain first in my groin, and now between the top of my hip and my knee. I have minor limitation of movement. Is there still a chance of AVN developing after that earlier MRI???