If you have the time to get it done then it's always a bonus mate, If your in a rush then I would clean up both surfaces up as best you can and ensure headbolt threaded holes are clear of any fluids to ensure the bolts are torqued down correctly. Also make sure you torque down the head in the correct sequence. Again, this info is on the site just use the search bar for the specific info your after! Hope this helps mate!