That's surprising, I thought MBUSA never sold the smart in the US and that there were currently about 53 dealerships.
In 2004 MBUSA flirted with the idea of bringing smart over. They even did a small SUV concept called the formore, in an effort to gain US attention. They didn't get enough reaction to go forward with the idea, and the formore died after a few prototypes were built. So yes, MBUSA was the first to "formally" introduce smart to the US.