Hey there! You are mistaking yourself with the preorder. The preorder only came with the gun, not ornament. The ornament came from the Eververse Store during Season 1. If coldheart was dismantled before the introduction of collections when Warmind was released, you will need to reacquire the weapon through Engrams and through Xur. Otherwise, you can grab another one from the collections page if it is still acquirable.