I can't believe I missed your last post; if you're still watching this, please clarify what you mean.
Are you asking if you should reuse your old cylinder? If you have a new one, I'd just use that. Before installing the new cylinder head, I'd set it upside down on the bench, and fill the chamber with acetone, paint thinner or whatever. Let it sit overnight, and see if any leaked past the valve seats. If not, you have a winner.
