I assume the worm gear is metal - so I think it's wise the replace the plastic gear with another plastic one - I rather replace that one than the worm gear in the event of an issue occurs. The bronze will not be as forgiving as a plastic one.
So it's most likely the 3 little bushing that failed huh - think it's best just to go ahead and replace all 4 items since it's all apart.

 

IIRC, it is either stainless or some sort of hardened steel which is going to be harder than bronze. Unlike plastic, he cannot get brittle but more important, it probably will be there. If you have to replace the plastic, I have no idea whether it will be available or whether I will have to order it like my power steering hoses only to be told it is discontinued by manufacturer and the aftermarket company that made them. The latest C4 is 20 years old. My 91 is 25 and counting. Who can say what is going to be available in 5 years when it turns 30? Only one thing I know for certain. Parts are going to be harder to get every day that passes.

 

Question:

Is the other gear plastic on purpose? Like to make it self sacrificing in the event the motor doesn't shut off?

 

I suppose it depends on how GM set it up. If there is a core charge, I would assume they plan to rebuild it. OTOH, if it just lists $X for a new motor, maybe not.

Disclaimer: I took a quick peek at the FSM so I might have missed something.

That said, I see "replace the motor" as an option and nothing to check the pucks or dowels or gear. So I do not think it is a serviceable item.

 

Both of my headlight motors are weak. One thing I did notice is that ANY contact with the wiring, vacuum lines, overflow hose, etc, will stop them in their tracks because they are weak.

But with new gears, I bet they would appear to work fine. (I can push them up with my hand) In reality however, they are still binding as they come up when they touch things in there.

I've been meaning to rebuild them and fabricate some brackets to tie everything off to, so it stays put and doesn't shift as I am driving.

I wonder if this random contact with items in the headlight wells explains why some people rebuild their motors and they are fine for a long time, but others have to do it every couple of years?