Ex2013 - "This user does not have an Exchange mailbox.”

I've been researching this and I think I found a solution, but need a sanity check.

I'm upgrading from Exchange 2007 to 2013 (co-existence migration), and when I try to migrate a couple test mailboxes I get an Error: “This user does not have an Exchange mailbox.”

https://social.technet.microsoft.com/Forums/exchange/en-US/d0c96836-3ad5-49c8-bd85-2df52f481b0c/exchange-2013-migration-says-the-user-does-not-have-an-exchange-mailbox?forum=exchangesvrdeploy

http://support.microsoft.com/kb/2812509/en-us

The “get-mailbox –arbitration” and “get-mailbox –arbitration |fl name,alias” commands show corrupted several corrupted mailboxes on the 2013 server:

SystemMailbox{1f05a927-ac1a-45fa-9abc-338f309be380}

SystemMailbox{bb558c35-97f1-4cb9-8ff7-d53741dc928c}

Migration.8f3e7716-2011-43e4-96b1-aba62d229136

FederatedEmail.4c1f4d8b-8179-4148-93bf-00a95fa1e042

The remaining mailbox (SystemMailbox{e0dc1c29-89c3-4034-b678-e6c29d823ed9}) is not corrupted.

Running the command to enable the migration mailbox fails.  Error: “This task does not support recipients of this type.  The specified recipient “Migration.{GUID}” is of type UserMailbox.

This thread suggests deleting them from ADUC and then running ADprep again to recreate them.  

https://social.technet.microsoft.com/Forums/en-US/bba16b29-0d1f-4f2b-943c-e2110ae0d8b6/fixing-corrupted-mailboxes-after-migration

Is it safe to delete all of the arbitration mailboxes (including the non-corrupted system mailbox) and then recreate them?