If they were backed up to a google account, you should be able to find them in said account through any other device you can connect to that account through. Tablet, phone, computer, etc. That only works though if the sync was updated regularly. If not, they may not even be in the google account. If that is the case, then they would be gone if they were only on the phone.
Also, if someone stole your phone, and if you had the phone set up to automatically allow you access to any accounts (that one included) then you risk that person accessing all your stuff. You should change your passwords immediately on any account you accesses from the phone.