Hi Steve

Yes, you can copy them or move them to other floors
First, select the walls --> you can select them separately using the Shift key or using Edit--> Select all. The exterior walls will be moved / copied as a set
To copy--> Select the walls --> Edit--> copy to Floor--> Upper Floor or Lower Floor, according with your necessities
To move--> Select the walls --> Edit--> move to Floor--> Upper Floor or Lower Floor, according with your necessities

Patricia