Exchange 2010 decommissioning the original mailbox db: Do I need to move any resources off before deleting?

We are  decommissioning our first (original) exchange 2010 mailbox database that we first brought online when we did our coexistence setup with exchange 2007, and need to make sure we don't miss anything.

I remember already moving the arbitration mailbox off, but these still remain when I do a 

"get-mailboxstatistics -database tmpdb"

DisplayName               ItemCount    StorageLimitStatus                                                LastLogonTime
-----------               ---------    ------------------                                                -------------
Microsoft Exchange        3                    NoChecking                                                             
Discovery Search Mailbox  5                    BelowLimit                                                             
Microsoft Exchange App... 3                    NoChecking                                                             
Microsoft Exchange Fed... 3                    BelowLimit                                                             
SystemMailbox{d22f23fc... 5                    BelowLimit

Josh