I got my GTZ in the mail the other day, and pulled the block apart to take a look at the inside. When I did that I noticed a plastic insert inside the block that fell out when I pulled it open. The insert looks like it should fit a section in the top of the block, but doesn't quite fit (at least, not without me taking a hammer to it). Is the insert supposed to be loose like that (that is, not fully snugged into that slot), or am I supposed to put some pressure on it and force it back into its slot?