2xMonterey

I have a 2003 253 Explorer and both of my docking lights are out, I have never replaced them so I am assuming they are just blown out, but once I took the two screws that holds them onto the front of the boat, I noticed that they are incased, which I figured it would be, but how do you get to the bulb to replace it? Any ideas would be great. There are two screws on the back of the plastic incasement, but once removed it doesn't seem to do anything. Thanks for any help, Charlie