Stable gravity a month apart is a safe rule. Since it’s from last fall, it’s probably safe to package. The pellicle won’t disappear, since it forms in the presence of oxygen. But if you cold crash, it tends to sink and you can bottle before it forms again.
I’d definitely try it before dumping. Cider is so dry, there’s a not a lot of food for bacteria, so there’s not much damage to be done. I made a natural fermented cider last fall and let the airlock dry out on accident, and despite the gnarly pellicle it’s one of the best ciders I’ve done.