Yes you should have ideally since the main thing reviews are tracked by is userid however since reviews technically dont sort or display by username its not that big a deal as Photopost
Install phpbb and then take the necessary steps to convert to integrating with phpbb
1. make sure the bbdatabase info is that of where phpbb mysql tables are and access info is right.
2. Change the following settings in the reviewpost settings table
setting 41 to phpbb
setting 83 to the phpbb table prefix usually phpbb_
3. Re-align your cookie settings to match phpbb settings
You mysql settings table is what I am talking about.
You looking to change to phpbb midstream so there are some backend things that need updating. You can select phpbb as the integration in your reviewpost admin and enter the table prefix there also