I agree that you don't need to change your chainrings and I also doubt that you'll have any rear derailer issues.

if you can find a Shimano part number on the barcons then you can just google them to find out the number of speeds.

If you're counting the number of clicks to determine the number of speeds then remember that you get one more speed than the number of clicks. (Somebody please correct me if I'm wrong about this. I've thought too hard about it while typing, and I'm starting to doubt myself.)