I once had a riveted "left side ride" (it was stamped as such) and in reality it was not a lot different from any other ride apart from being slightly smaller in size from my others at the time. It is just a marketing term as nothing stops you using it on the right side alone or with another.
Obviously if you are going with 2 rides then they should be different in some way but also "blend" together in some way.
I myself used 3 rides as a jazz cymbal set up and no crash. Each was in a dark tonal range but had enough difference to warrant their use - one being a flat ride, one being riveted and the other being a "normal" one and each was "crasheable".
Light travels faster than sound. This is why some people appear bright until you hear them speak.