I might’ve missed something, but in the spec I could not see anywhere which forbid a product that isn’t typed by a type product. I think this is a good thing, as very often there are objects where the type isn’t known or doesn’t make sense (e.g. a one-off product, or a scan of an unidentified item). Can others here confirm that an untyped product is legal behaviour?
The reason I ask is because in Revit, for example, everything is typed by default and I am unsure how to tell it not to type a product.