I've got 20-30 individuals at least, some native, some collected, and some volunteers. Some have foliage like your image, dark green somewhat narrow and slightly glossy. I had thought in my mind that that type foliage was sex-linked, so I took notice when mine bloomed this year. Nope, just natural variation. Also there is variation in habit, some bushy, some tall and more tree like, some vigorous, some less so. There MAY be some evidence that the type in question tends to more bushy and compact, I've seen that on mine and others I'm familiar with. But don't take that to the bank.

And here I was hoping it was exceptional. ;) The glossy-leaved Fringe Tree has better form than the other, which is more open and has a somewhat unkempt look. Would you characterize the leaf in the first picture as slightly glossy? I'm not too familiar with such botanical distinction.