Iris are really resilient, I would go ahead & plant them. Unlikely to bloom in the spring, but they should be ok. I've told this story before, but one summer I divided my iris & had a family crisis, one after another. Those iris got left on a glass top table in hot full sun the rest of the summer, & spent the winter there too. The following year, almost all of them were showing green growth. I planted them that spring & the following spring they bloomed again. If you have a place to put them that is a bit protected from the weather, I'd plant them there. I planted some in November once, not recommended, but they survived.

Iris tolerate light frost pretty well. However, planting late in the fall means they probably won't have much time to be growing roots before heavy freezing, and that will discourage spring bloom. If you have issues of plants heaving out of the ground from freezing in the winter, you might want to plant in pots and keep them somewhat protected until you can get them into the ground in the early spring.