I've taken my 350s apart, but I really didn't check whether they functioned without the front cover. I really don't see that it would make a difference though.
I posted images of the pieces
in this thread, the last one being the front metal shell. It really doesn't seem like it would make a difference, but perhaps the bevel as you mentioned is needed for the IR.
Does it turn on at all without the front piece on and it's just that you can't turn pages? Do the buttons work to turn pages? It's possible there's something else wrong with it.