The fabric, I think, is linen or a linen mix? It is heavyweight and feels new, even though these are likely from the 1970's.
They seem to be sewn on three sides to make pillows. They measure about 24" x 22" and could be cut and sewn into things other than pillows.
There is a mark on one of the orange panels and I photographed it. It seems like it is original and just part of the process of making this kind of fabric.