Metal Dumbhead on Shaving Horse

The picture accompanying this article about the rebuilding of Notre Dame's roof shows something that looks like a hoe being used as the dumbhead in a shaving horse. The architects and craftsmen who are working on that project are insistent that they are doing it authentically. So it seems that you can use metal for the clamping part of a shaving horse.

Yes they can, and the draw knife he is using is also metal.
Do you expect that to be a timber tool?

Hey John, sorry it took me awhile to parse your questions.

Yes, all the shave horses I have seen have been made of wood. Certainly the jaws have been. That protects the work piece from being marred. But if that is not a concern clearly a metal jaw may be used.