I've been told "no" they are not the same. I have a little container marked "9 speed" and another marked "10 speed". Chain pins in each per my LBS.

I learned on one trip that there are two different replacement pins for 9-speed...one as you describe, with the 3 ridges, the other without the ridges. All I can remember is that the one without the ridges is the one I use for my Ultegra 9-speed.

Sorry if this just confuses things.