mount -t null -o noatime

Suppose I have a (FFS) fs mounted with atime (e.g., without -o noatime) 
and I null-mount that fs somewhere else with -o noatime.
Will that do what I expect, e.g. will operations on the null-mounted fs 
leave the on-disc atimes alone?

The use case I have in mind is restoring from a backup; updating the atimes 
of the directories would be a waste of time since the backup program will 
restore them afterwards anyway.  Or is there an easier way for this?