Is it normal for the P7P55D to have a small gap between the I/O shield and the I/O interfaces? I thought it was pretty weird seeing that. I noticed that there was a metal tab on the PS2 port and I was not sure if I could remove it or not. It was getting in the way of installation of the mobo. Definitely made a one man's job into a two man's job for someone who has a big hsf. I had to push the motherboard into the I/O shield while my housemates helped me get the screw in place.
Also is it safe to insert my CPU fan into the CHA FAN? I have a Noctua NH-D14 and it covers the CPU FAN slot.
There should not be a gap between the I/O shield and the I/O interfaces or ports, I think. The metal tabs are for centralizing the ports in the I/O shield. If you bent the tabs during the M/B installation, they keep the ports away from the I/O shield. My M/B is Asus P7P55D but it does not have the tabs. It is tabless. Therefore, I think you should remove the M/B, straighten the tabs to their original position and re-install the M/B so that the tabs open sideways to make way for I/O ports.
I did not bend the tab. It was already bent to begin with and I just thought that maybe I should straighten them; however, I noticed that there was not slot for the I/O shield to insert that tab in so I decided not to straighten it. You can see the tab here