/System/App/Mms.apk (The TF300t doesn't have a SIM card slot, but the TF300TG/TF300TL does, obvious, I know.) It's not installed on the system, but it's there. And when you attempt to install it, it does not install. So, was ASUS just getting lazy or what? :P Screenshot.
Sent from my ASUS Transformer Pad TF300T using Android Central Forums