If you were working with a unlabeled simple stained smear, would you be able to identify the bacterial species by observing the slide under the microscope?

No. One could only identify the category of the bacteria by observing for morphological features through simple staining. The size, shape and how the bacteria are organized in colonies are used to identify bacteria categories. Bateria can be classified as vibrio, cocci, streptococci, and etcetera