Do I need to update submitted transcripts with a legend?

[gradschoolapps20xx]

One of the universities I applied to this week requested that a transcript legend be uploaded with the actual transcript. A couple of earlier schools I applied to (for which the deadline has now passed) didn't mention anything about transcript legends in their application section, and my uploaded transcripts for those schools did not contain a legend. For these schools, is this something that should be included as part of the transcript upload? Is there anything I need to fix here?

My transcripts use an A-F grading scale, P/F for pass/fail, which I assume would be well-known.