Under the dash of my 1954 chevy truck, where the holes to mount mirror on driver side has two stud bolts what are they for and how do I get around them? This part of truck was covered and primed when I got trk. I know almost nothing about rodding or working on vehicles. I need basic ABC instructions and if possible pictures (or drawings) for this simple task. Installed mirror on pass side, no problem. Thanks for help.