After learning the hard way, I always copy the "wrapper" on any legal document of which I make copies. In addition to usually indicating what the document actually is, there will be a filing date and other details of the case.
Making a copy or taking a picture means I don't have to write all that information down.
But I do need to capture it so that I can later cite the records used.
It's fast. It's easy and gets the job done when you're researching on site and time is of the essence.