This is correct. Some film cameras have leaf shutters in the lens, and this allows flash sync speeds higher than the focal plane shutter speed of 1/125. For example old Hasselblad lenses could flash sync at 1/500. The downside to those lenses is they aren’t capable of opening the shutter fast enough to go higher then 1/500 or 1/1000. With mirror less cameras, that isnt an issue.