For some reason I can no longer find these instructions in the manual, so I asked PrintSmith Service to give me the instructions:

To prepare to go live and reset your system follow the instructions below:
(This will keep your Customers, Press and Digital/Copier definitions, and Charge definitions.)

1. Back up the entire PrintSmith Folder.
2. Open the Data Folder and select the following the following files for replacement later:
Customers,
Customer Index,
Customer Notes,
Customer Log,
Contacts,
Contact Index,
Employee, and
Employee IDX.
(The Employee files are only necessary if you are at 7.1.x or greater and have the Tracker module)
3. Drag these files to the desktop.
4. Delete the Data Folder
5. Rerun the PS Installer from the CD.
6. Place the files from Step 2, which are on the Desktop, into the new Data Folder of the PrintSmith Folder. Replace the files in the Data folder.
7. Launch PS and first rebuild Acct History. Hold down the Option or Alt and Shift keys and select Reports > Account History. Click OK.
8. Verify your customer and pricing are installed in this new version. From the AR menu, select Verify All Balances and Verify Receivable Balance to make sure they are set to zero. If you are asked to fix any balances, click on Fix.

That should do it.