I'm kind of stumped here... I usually customize all my icons. My method is to just go into the Finder.app and replace the icon with my own, and go into dock.app and replace both .png's with my own. For some reason this is not working in Mavericks, it's getting the icon from somewhere else. I've even tried delete both png's and Finder.icns completely to see if it would give me the default generic application icon, but it still uses the default no matter what I do. I double and triple checked spelling, capitals, etc. I've also tried setting permissions and ownership manually through the terminal and repairing disk permissions. What icon is it referencing?