Wow! That's definitely different than mine. I was sticker # 55???, and my instructions clearly posted a fourth location. That location was on the FRONT bumper. I figured the front location would allow an officer who was in front of you to identify that you are legally in the HOV lane.

I'm guessing they decided it wasn't necessary... and therefore no reason to affix the sticker. Wonder if that means I can take mine OFF now! Actually, I fought so long and hard to get the stupid things that I've become "attached" to them (even though they're ugly!)