When you say *use*, do you mean "modulate over time"? Because there's few synths that actually give you heads up on whether they;ve used a particular modulator - say, aftertouch, in any given patch, just like no sounds have a graphic of "hey this patch uses wave sequences".
Remember, the vector position is just a mix of up to four oscillators in a patch. You should always be able to use the joystick to alter balances.
Modulating the mix envelope over time is just one of the many features that a patch designer can use if they want to. Not every patch in the library uses it, and in fact probably not that many do, but some do for sure.