Within manufacturer's groups, same series lights typically have the same layout. For example, I can tell the channel layout basically on any Elation Design series fixture or any Mac series fixture. Same goes for Elation's LEDs. They all basically use the same layout, so much so that you can use the same fixture profile for a lot of them.
Now, from manufacturer to manufacturer, it goes all over the place. One thing that is fairly standard however is having 16 bit channels back to back. For example, pan and pan fine being channels 1 and 2 respectively. There are some that don't do this however.