You can do whatever you want, actually.
If you refill an item then it can be dibbed again by other people. But that doesn't mess anything up. If you don't want it dibbed, then make sure that either:
a) it's marked as "not ready" or "private"
or
b) that the quantity is 0.
You can also disable it from the swap by clicking on the green check icon in your list. That will make it completely invisible from this swap, but anyone who already dibbed it will still get their dibs on it.