If AZZ are concerned the deal could still fall through, then...

If AZZ are concerned the deal could still fall through, then obviously there are still obligations that need to be met.

So maybe despite the deal not having any specific conditions, there may still be basic contractual requirements to be met.

Even without knowing the details of the deal (\contract, assuming it is a contract and not just a MOU), the key point is there is still a risk the deal may not go through, and disclosing the buyer increases the risk to the deal failing.

While there is risk to the deal, the buyers details should remain confidential for reasons previously posted.