Hopefully it will be a dual tone. Around 2018 Ford quietly took one horn off the bracket of a lot of their vehicles. The horn removal caused a service memo being sent out to dealers explaining what they did. https://www.mustang6g.com/forums/threads/2019-mustang-horn-single-tone-solution.121535/
Ford never disappoints w/ these type of things, ever. Just like very selective availability of the sport and tremor packages in the F-150 and Super duty's.
When you look at the teal-most A51 representive pictures including paint samples there are some that get uncomfortably close to the many shades of 90’s gm teal(s). Whether or not that’s the actual color is obviously an unknown until someone sees it in person on here.