Honestly no and it was something I was listening for. I've used a few songs I'm very familiar with and revisited them over many hours of use. The only differences I note are when I change the source.
Currently I've been listening for differences in the new Onkyo IEM as it uses a large dynamic driver which seems more likely to be subject to break in. So far I'm coming up blank. Could just be me... I prefer that people not expect grand positive changes in C/IEMs over time, if so I think many would be disappointed.
In the past I do believe I've heard burn in with floor standing KEF, Paradigm and possibly Mirage speakers (though Omnisats make the last a touch more difficult as there are more room reflections).
Change doesn't necessarily mean it will get better so I agree with not assuming but by the same token, I wouldn't discard anything before 100hrs either.