Not sure, Bob... maybe you could try to call RT and give them the VIN and see what they say.

Contact RT and ask the same thing you’ve asked here and provide them your VIN and they can tell you if you have their tune. I would ask the selling dealer if your ECU is stock or tune, if they sold you a Mercedes with a tune, they should be liable if the tune causes any issues that might or might not void your warranty. Also keep in mind some people might buy downpipes from one vendor and tune from a another vender.

What I learned from my previous ecu tune. Is that, if your ecu had been tuned before. You can check physically if the seal around the ecu has been cut. Most tunes require opening the ecu’s. The dealer won’t be able to tell. Unless they really plug in your ecu and really look into it.