The coating is insulation NO there will NOT be a 'good connection' if you leave the coating on.I say leave them alone. Your complaint is a COSMETIC issue. not a functional one. Have you actually measured any resistance in the cable electrically? Have you bothered to check?
Perhaps paint the offending looking area?Personally I would leave it alone and use them.
Perhaps paint the offending looking area?Personally I would leave it alone and use them.

