Here's mine. I apologize for the lousy photo, as I'm at work, and parked facing into the sun..
But, you'll get the general idea.
However. There's a bit more to it than that. This particular car (also a 1997) didn't actually come with this unit. I installed it, with (lots of) Jeremi's help.
If you want HomeLink, but don't have it, just grab a visor that has the right color trim around the buttons, from any similar era car. I'm pretty sure I've seen these modules in nearly every brand. Mine came out of another Mark VIII, but that one didn't have a sunroof, and mine does, which means the visor itself was shaped differently.
The visor opens like a clamshell (clips around the perimeter.) and there's a little space inside the visor to hold the module. You just need to punch a couple holes in the fabric for the buttons, and tap the power into the light for the vanity mirror. In my own case, I was able to move the stamped copper "traces" from the donor visor into mine, for a particularly tidy install. Really though, there's enough room in there to just run a wire instead if required.