Not necessarily. They are older... it looks like you have some nice new roots starting. But rinsing the older roots may remove dark color from the medium. If they are at all firm, they are alive. Don't be in a hurry to cut roots, if that is what you had in mind... even older roots can be useful, even if just to anchor the plant in the medium, but they may also be working to hydrate the plant as well, even if not as efficiently as a new, fully-developed one. You can gently tug on the oldest ones (in the background of the photo)... what comes off easily can be removed. Leave the rest. The new ones are just getting started. It is a good time to put that plant back into its pot, with fresh medium.