Correction - it’s the bottom hole that is already there, and you have to drill & tap the top hole. Everything else remains the same.👍

For any of you who receive your Adjusters - this is an excellent written step by step process of what is involved in the installation process & includes photographs at every step. web.hypersurf.com/~charlie2/X31/HeightAdjustFiles/HeightAdjInstall.html It details what drill bit, tap & die that you will need as well as Allen key to complete the installation. 👍