Looks like they had a big roll of wet chipboard and just wound it up around some kind of form.
But no, the carpiest frame I ever saw was made out of 4 mitered pieces of 1x3 inch foamcore strips, coated with possibly Krylon glossy black and tastefully enhanced with gold highlights from a texture roller. It came from a liquor store display, a friend of mine was sure I could "fix" it even though the storefront framer next door had expressed strongly negative opinions about that possibility. I said sorry, I was completely out of duct tape.