Ball Joint seal or Bushing 1983 Dodge Charger

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I am in the process of replacing the hub assembly in the suspension knuckle in the above vehicle. On removing the knuckle I found what i believe to be a ball joint seal where the knucle attaches to the lower control arm. Not sure if its a bushing or a seal as it only looks like a rotted piece of rubber.
Doge parts has told me that Chrysler no longer offers this part #4014-242. My question is if its a seal and is not leaking grease is it necessary to replace it? If its a bushing is it pressed in and what purpose does it have?
Thanks for your input.