I see your concerns and I don't want to advise you to buy something and it turns out to be wrong. My best advice would be to contact Scosche Technical Support
Contact Us by Scosche and tell them exactly what you have and the model/year RAV4 that it came from. They should be able to advise you what part(s) you'll need. I did a little more research and I see that Toyota offered a JBL Synthesis system as an option in some RAV4s. If that's what you have, there may be some connection issues.
__________________