That could be it. It measures 6 7/8" wide. The one I have measures 6 7/8" wide if I lay it flat and press down. A 505 reader with a standard cover measures about 5" wide, so it won't be a snug fit. There is a similar planner cover measuring 4 7/8" x 8", but that might be too small. Is there a Staples near you to test fit your reader before buying?
I really like the planner cover as a carrier for my 505 with Lightwedge. Here's what it looks like unzippered.
