I noticed that in the original version of the number pad top shell, stabilizers would not fit and switches were a little tight. In this version, the mounting plate is 1.6mm thick so that standard PVB-mounted stabilizers can fit in snugly and switches will snap in nicely.

Thank you Jebidiah_Crumps for uploading the STEP files.

Printables: https://www.printables.com/model/276490-number-pad-top-shell-v2