Yes, I agree, the spacing is odd, so probably non factory made.

Ah well. I don't care too much for rivets anyway. It does make sense with a flat ride though. Now you have the articulated stick sound from the flat, with sustain from the rivets.

For anyone curious how it sounds, I have a crappy sound file :)

click

It gives you an idea. In reall life there a bit more 'crash' in the crash sound, and the attack is more defined and woody.

Here is a sound file by the way:

click