installing a new booster today and two questions come to mind.

• should the booster pushrod/backside of the master cylinder be greased?
• is there supposed to be a gasket or sealant between the master cylinder and the booster?  (fyi my car came equipped with a 1" spacer between the master and the booster)

 

White lithium grease will not hurt anything.

 

There is a vacuum seal behind it but applying a sealant to the margin between the booster housing and the master cylinder has been on all systems I have taken apart.