New thread size for roof-rack attachment points

[vlsidude]

I just traded in my 3-year old Model S on a new Model S and my roof rack no longer fits. The old M8-1.25 button-head cap screws are too big. The new attachment points look to be 6mm in diameter but appear to have threads much coarser than an M6-1.

Does anyone know the thread size for the new attachment points?