In what kit? If it is on an M1 Abrams series tank, the rollers are hidden by the skirt.
If on an M4 Sherman series tank, the support roller is basically one big steel bearing. One hole is the grease plug and the other the relief valve so the two holes are supposed to be there.
The list goes on and on based on the amount of tanks that have supprt rollers.
So as you see, the answer depends on WHAT TANK ARE YOU BUILDING?