Sheetrock over Homasote

Uihlein

I have an attached two car garage that shares 1 common wall with my home. The hose and garage was built in 1957. The shared wall between the house and garage is not insulated. The garage was finished in homasote which (except for the ceiling) has been removed. I am in the process of replacing two windows, one rear entry wooden door and the garage door. In addition, I am unsulating the exterior (2x4 16 on center) walls, running added electrical outlets and sheetrocking. I will use 5/8 fire proof for the entire job. My question is, I have not pulled the homasote from the ceiling with the hope that I would not have to and could sheetrock right over it - mostly to save time and a mess. Does anyone know if this is okay or am I just asking for trouble later on. The ceiling rafters are all 2X10 (believe it or not).