Some will consider anything that isn't pure individual dyes a compound henna. That would include products that have henna and indigo both in the same packet, for example, as well as products that have metal salts or chemical additives.
The brand you mention at the very least is "compound henna" of this more broad definition. As to whether it contains chemicals or metal salts, I'd encourage you to contact that company directly. By US law, the ingredients need to be on the outer packaging, so getting your hands on the product, even on a store shelf, may be all you need!