Rain Sensing Wipers addon?

I recently found out that the Lariat ER 510A that I have does not come standard with rain sensing wipers. I found that extremely odd as I have not had a vehicle without them in over 10 years. I found it in the eSource book from another post. Does anyone know if this can be added after? When my dealer said the 510 and 511 were exactly the same aside from sunroof he was obviously very wrong.

I hate that I can't just ask my dealer they are so utterly useless, you lads here are far more informed.