See my parallel comment, ringdown is different for black hole remnants vs. something else, so in principle we can tell if it resulted in a black hole or not. Ho

See my parallel comment, ringdown is different for black hole remnants vs. something else, so in principle we can tell if it resulted in a black hole or not. However, for objects of suitable mass (a.i. small) the current detectors don't work very well at the frequency required to make this assessment accurately, so secondary evidence is required.