Just chatted with apple support...
I don't know if I should believe her. She didn't seem too knowledgable...
You are chatting with Janet R, an Apple Expert
<Hi, my name is Janet R. Welcome to Apple!
>Hi
<Hello!
<How may I assist you today?
>I have a bumper on my iPhone 4. Will it work with the iPhone 4 dock?
<One moment while I check.
<On the iPhone 4 doc it fits. The Universal dock it does not.
>So my iPhone 4 with a bumper will fit in the dock and make the connection with the dock connecter?
<[links to the dock]
>Thanks
<That is the one it will work with .
I don't know if I should believe her. She didn't seem too knowledgable...