Yes, the DSA will synchronize deletions (as well as addtions). You should be aware of the following caveats:
- Ensure the SMTP Template being removed is not configured in the target's Recipient/email address policy
- In Exchange 2000/2003, if you remove an smtp template from the recipient policy, it does not remove the address from objects that had it. This is the case even if you manually apply the recipient policy. You will need to manually remove the address template from each users proxyaddress attribute. This behaviour has been updated in Exchange 2007 and 2010 email address policies, so they will add or remove automatically to all in scope objects.