Outdoor Light - Ground Wire

I'm replacing an outdoorlight fixture. I removed the old fixture. There is a plastic electrical box. There was no mounting bracket for the old fixture. The white wire was connected to white; black to black; bare copper ground to bare copper ground. The new fixture has a metal mounting bracket with a ground screw. Can I just connect the new fixture wires to the wires as the old fixture was or is it necessary to pigtail the ground wires together and attach to the ground screw on the metal mounting bracket that came with the new light fixture?

I did pigtail the wires and connect to the ground screw but I'm not sure it was necessary or, if it's not necessary, if it's ok to leave it that way.

 

Yes, pigtail the ground wires to the mounting bracket.

 

Probably not necessary but it can't hurt. The equipment grounding screw on a mounting bracket is for use when there is no separate equipment grounding conductor and the wiring method is metallic conduit. The mounting bracket is grounded to the metallic box which is grounded by the conduit system. The equipment grounding conductor from the light fixture proper is then grounded to the bracket.

With non-metallic cable and plastic boxes the equipment ground is from the cable's bare grounding conductor to the lamp fixture's bare or green-insulated grounding conductor.

 

Ok - thank you both. I'll leave it pigtailed.