I believe the hole you’re referring to goes all the way through the playfield. I used a hot needle clamped in my vise grips to poke a hole through from the bottom, then a sharp drill bit from the top to enlarge it to size.
Quoted from curtobi4:One problem I had was that not all the holes in the hardtop lined up and some were missing. In particular, the hole for the outlane gate guidepost. Not sure if I need it. If I knew the distance between the guide and the post, I could probably drill it.