Yes, I am certain of it. This is why I couldn't talk myself into not labeling it as such... At least it used to be, but many do not label it this way unfortunately.
Funny thing is I remember it stating that clearly when I went through the process years back with my personal FedEx Account. I don't have all the documentation from back then to check it, but checking the paper work from when I setup my business account, it is not clearly stated in it. It says the package must be labeled properly (Item "C" if you have the same waiver of liability form I am looking at), but no longer states what that proper labeling should say.... I am pretty sure there are instructions out there on setting up the package before sending it in for testing though that do indeed clearly state this, but alas I don't have my copies of those.