Many times, yes. If the item doesn't already have that property there may be an issue with how it works on the gargoyle paperdoll. It could look ok, slightly off, or terrible. It could be difficult or impossible to un-equip via drag and drop. It may or may not be visible on the in-world character (your "toon").
Whatever you do - never let a gargoyle body ride a mount. It'll bring the server to a screeching halt!