fs change on read-only mount

[Bgs]

 Greetings,

I don't know xfs' superblock handling well enough, so I'm asking for
advice here:

Does xfs write anything on the disk when mounting read-only? Is it
possible to use a partitions hash (or some well defined portion of the
partition) for integrity checks?

The partitions are used read-only and hash would be re-generated  if any
rw action was done (after remount ro or full reboot of course). Can this
be done? I'm concerned about 'mount count' like writes...

Thanks in advance
Bgs