As long as you don’t change the original camera file names to be different than what you see in the “Source File” column you will always be able to bring original camera files back in and recreate your sequence via a conform or re-conform depending on what you want to call it.
So archive the 500GB of material, on at least two different drives, (better three), and keep them at two (or three) different locations for safekeeping. Make sure to spin them up once or twice a year and make sure the environment is stable, etc. You may consider an LTO type archive. I usually make two for LTO, and three for hard drives. The saying for backup is” One is none, two is one, and three is two.”
Michael