Do I need to program a USB-Serial FTDI chip before using?
You may need to program FTDI chip only in case you need some advanced functionality like flashing your Company Vendor ID and Device ID to make your particular custom device to respond only to your custom modified version of drivers and to stand out as your custom device in system. Also you may output clock signal from FTDI chip, modify logic for TX/RX leds and make some other interesting things which you can see in details in the datasheet.