No, not quite! I fell into this trap last night. I used the backup option under system settings to backup the PS3 hard drive. After rebooting it I selected "PS3 System Restore" (or similar) and all it does is format the hard drive and wipe your PSN details
To do the restore you must first select the Backup option and then select "restore" from the sub menu. Even then when it is actually restoring your data the screen says "backing up data..."
There is also a further option to restore factory settings - what that does that the other system restore doesn't I have no idea!
Someone at Sony really should look at re-designing that part of the menu system...