You can if all the mailboxes are moved. Verify the arbitration mailboxes are moved as well:
get-mailbox -arbitration
If they are in the old database, move them
get-mailbox -arbitration | new-moverequest -targetdatabase <NewDB>
then remove the database with Exchange so it can check for any dependencies, dont just delete the DB
Remove-MailboxDatabase -Identity MailboxDatabase01
https://learn.microsoft.com/en-us/powershell/module/exchange/remove-mailboxdatabase?view=exchange-ps