Balance-Two ACW-758 rackmount issue

Hi,
I purchased the ACW-758 kit to rackmount a Balance-Two and it appears the rackmount is reversible to either mount the balance with panel front/ports behind or ports front/panel behind. I went to attach the rackmount adapter with ports in front and found although the holes line up on the Balance they’re not threaded to attach the rack adapter.

Can anyone confirm this is normal and it can only be mounted with the panel in front or is it a manufacturing mistake that the holes aren’t threaded?
These would be the ear holes on the side of the unit. Bottom holes were threaded.

Thanks