mac pro optical shutter etc

Greetings everyone. I have a Mac pro 2010 5,1 (Westmere ) which is working fine. However, in shipping, I'm guessing, the optical drive shutters/doors got a litlle bent and so they might open, but they wouldn't close on their own. I had to help them with a bent paperclip nudging the shutter forward. so, can I replace this myself or is it part of the case? I haven't seen a spare/replacement one for sale yet...

2nd question. I have a dell U 2713 HM monitor. I used a dual link dvi cable to connect it to my Mac Pro and I got a variety of video options. I thought "well, if DVI is good, surely HDMI must also be as good, right?" . Not quite-where I used to have 10 different screen sizes to choose from, now I have five -3840x2400,

3200x2000,2560x1600, 1680x1050 and 1600x1000, all of which were marked (low resolution). I am using Switch Res X to get 2580x1444 but I don't see any other way to get different resolutions. My GPU is a sapphire Radeon 7950

any help on one or both would be appreciated

thanks

John B