I would leave them. Freezing won't harm the seeds. I left pole beans up on the trellis all last winter, not noticing that there were several pods with ripened seeds, and in the spring my very helpful daughter found them and planted them and they all grew.

Thanks, that's good to know. I did a bit more reading and some people suggest pulling out the entire bean plant and hanging it upside down to dry. That would be tricky to do with the pole beans though....

Green beans I found can't take a frost at all. I have picked all, at this point theyr'e not growing anymore anyway, the large ones I just dry in house unopened,..works pretty good.

It might be too late now, but...if there's any significant moisture left in the seeds, they will likely be damaged by frost. Otherwise, they will be OK.