Yes, the catalog backup will preserve your NetBackup policies and catalog information, but you should keep the following things in mind when rebuilding the server:
1. The catalog backup doesn't backup any of the NetBackup helper scripts (nbmail.cmd, bpstart_notify.cmd, etc.), nor does it backup any touch-files that you may have created to improve performance (such as the files to adjust the size and number of memory buffers). If you have edited any of the scripts or created any of the touch-files, make sure you back them up manually (i.e. copy them to a USB flash drive) before you rebuild the server.
2. Don't change the hostname or IP address of your NetBackup server when you rebuild it. Very ugly things happen if the hostname of the master server changes (i.e., you may not be able to restore from backup images made prior to the name change).
3. Make sure that the DSU (backup-to-disk) directory stays on the same drive letter and directory path after the rebuild.