No, FD6, FD5 and FD4 are all over ten years old, are officially retired and Final Draft, A Cast & Crew Company, no longer offers support, authorizations, CDs or key disks for them.
If your computer was not authorized before December 23rd, 2009, you will have to insert your CD each time you want to open Final Draft 6 / 5. Once the program is open the CD can be removed.
If you have FD4, you will have to insert the key (floppy) disk each time you want to open the program. Once the program is open the key disk can be removed.
Using the CD or key disk to temporarily authorize a Final Draft session may or may not work depending on your operating system and the physical condition of the CD or key disk.