Sending in Materials to Colleges

<p>Hi,
I'm just wondering if I have to include anything else on the envelope for the teachers rec's. I have my school's official logo stamped on for the return address, and the university's address, and a stamp.
Question is, do I need to add anything else, to indicate what the contents are inside?
Like should I write somewhere, "Anna Banana's Letter of Reccomendation" or something like that on the envelope?
Do the adcom's usually just open the envelope, and then sort whatever is inside?
Sorry if this seems really dumb.</p>