That's normal after an install, it becomes the official icon (the one you see in the dock) in a little bit. To be honest, I'm not 100% sure what it is exactly that triggers the icon to display in the Applications folder, but after a little while of using the program it just shows up.
If you're particularly anal about this sort of thing, you could restart your system. If you're thinking about doing that, I'd recommend you don't and force yourself to get over your anal-ness. 😉