First Primordial Black Hole Event?

A very strong gravitational wave event was detected on 8/14/19. It was relatively close and observed by multiple detectors. Judging from the masses it is a merger of a black hole and a neutron star.

However, no electromagnetic phenomena have been linked to the event, as was the case in the well-known NS-NS merger.

If no EM signal is observed, and if the mass of the lighter object is not in the correct range for neutron stars, then the event may be the merger of two black holes, with the lighter BH being a strong candidate for the first primordial black hole positively identified.