Since no one has answered I'll give you my best guess. I have recently had a bunch of runner beans sprout in the compost heap from beans I threw on there. They were overgrown and tough, so no good for eating, but they were still green. Therefore I think your over mature green beans would probably grow even if you picked them before they go brown and dry.

I would definitely strip the vines before heavy frost. Otherwise, before picking,I try to wait until the pod is thinning, I feel it near the stem and see if it still feels fleshy or not. I have enough for seed so I'm eating them as shellies. But I agree, if the seeds are mature size they are likely to dry fine for growing, I let the pods dry somewhat indoors before shelling. The fleshy podded seeds I've picked sometimes look a little immature.

Thank you both. I picked them all since we had temps in the 20s predicted. Some of the pods were indeed thinning and I shelled the beans. They looked mature but weren't as glossy as the fully mature ones. I set them in a shallow bowl to finish drying. The thicker green pods I just set in a basket to see if they will mature and dry. If not, I can toss them as I have plenty of seed for next year already.

They will dry faster in the bowl if you put a small fan on them.