Recently found some long-lost images of 5 1/4" floppies that were sent to me... 10-15 years ago. Here's one of them: http://www.corestore.org/RP06.552
Looks like a straight image for a 1.44 what we call "stiffy". The 522 is the version of RP06.
Google leads me to http://www.corestore.org/rp12.htm so you already know what it's for :-)
W