All dummies have no primer. There are two main ways of marking them: a hole drilled in the side OR a BB inside that rattles. Also
There are three types of ammo that could have gone in the revolver:
Live ammo (we all know what that is)
Blanks (half or quarter charge of gunpowder/primer; contains no projectile but can emit gasses - makes a bang and emits smoke; the place where the bullet would have gone is crimped - very hard to confuse for live ammo)
Dummies (no primer/gunpowder; has a dimple where the primer would have gone; contains no projectile; most common in use; makes no bang and emits no smoke; not crimped).
(not a news source, just a little tutorial on ammo)
Dummies can be further subdivided into fake looking ones (plastic, purple, etc) and ones that are cosmetically identical from the outside of the gun to live ammo or blanks.
So she needed to deal with three types.
Dummies have a cosmetic top that resembles a bullet, but it is not actually a slug, it's usually plastic.
I listened to Hannah trying to explain some of her work on a podcast (Voices of the American West) and found her confusing.