Solution
No, after it has been deployed, you can't recover the source code for either the host VI and/or the FPGA VI.
However, if your system is RTOS-based, you can retrieve the application image using
RAD-Replication and Deployment Utility for backup or redeploying the application image.
Unfortunately, if your system is Windows-based, there is no method to retrieve the application image for backup or redeployment.