Yes, the DC-3's I work on have grounding cables at the tailwheel, which rub the ground. We still bond them to the fuel truck.
In a certified airframe, metallic or otherwise, every fuel and powerplant component will be bonded to each other, and the electrical system ground. If an aircraft (certified or otherwise) is not so configured, it is not representative of a compliant or ideally safe arrangement. On many aircraft, you will find metal structure bonded to metal parts by small bonding straps. Flight controls to their flying surface being a prime example. This assures no arcing through the hinges.
One of my client's maintenance shop will have every aircraft in the hangar bonded to the steel structure of the hangar by a clip on cable. This is based upon their very unhappy experience of having a customer's Cessna Cardinal catch fire while they worked on it. They were able to open the door, and roll it out on fire, so only it burned, not the hangar and contents - but they could not extinguish the plane in time.