Stereo panel has 2 holes empty
 

1996 z225 talari new to me has 2 holes that aren't labeled 1 is square and 1 round at the bottom of the panel. Hope to have attached pic.

Re: Stereo panel has 2 holes empty
 

I'm not sure of your model but possible guess would be the mileage counter for the square hole and possibly a cigarette power outlet for the round one?

Maybe look through the library for your model and see if you can find any good pics of the dash.

Re: Stereo panel has 2 holes empty
 

That looks like one of the aftermarket aluminum panels from e bay. The round hole would have been for a cigarette lighter (12v) and the square was a water/air temperature display if your boat was equipped with it. Those panels cracked and fell apart a lot so someone probably replaced it with what they could find.