Not particularly, no. They just stand out because the X block isn't printed very often. Until they were recently printed for series 2009 $1 and 2009A $100 notes, the last time they were printed was for series $1 1995 and $100 1996 notes. Y block notes are even less commonly encountered because they were last printed in 1999. It seems apparent that the BEP purposely avoids printing the Y block as well. Hummm good reason to buy it.