I know that this is a bit of a stretch, but since the Gen1SLE doesn't come with a sunglass holder but has a HomeLink controller in its place, it's probably just that (since there's a bit of a notch at the end)? Then again, the only thing I can think of that would fit was my clip-on shades or one of those sunglasses that fold almost completely flat.
I don't recommend putting coins in there though; it messed up the opening and closing action of it and I had to "surgically" remove a dime from the back of the track... I guess there's a gap above it, and the last time I took apart the dash, I became almost $2 richer from the old owner's change... But I'm too stingy to keep change in the car now.
(and yes, I turned it to HOT and put the arrow that was supposed to mean "lower vents" there on purpose... DAMN should've turned the fan on full speed to complete it!)