When you create an instance via Heat (or CLI or GUI), you can't ask for a hypervisor. You don't say "create a KVM instance" or "create a Xen instance" or "a baremetal instance". You can indirectly select the hypervisor via flavors, if the administrator created flavors for hypervisor selection.

So the short answer to your question is yes. However, only if the cloud has baremetal nodes and contains flavors that allow selecting them. There is no Heat resource type that manages or selects baremetal nodes.