I haven't tested too many vehicles, however if I had to guess I would imagine it's common on later model vehicles.

If possible, I would always recommend connecting directly to the component you're interested in. However, another good option is to see where the aftermarket world connects to. For instance, you could look up an install guide for your vehicle on https://www.idatalink.com/ (a popular remote start module interface) and utilize their wiring diagram to determine location/colors.