Last place I knew that you could get just that piece was from GM but I believe it was discontinued a few years ago
If you'd like to pop off the $.03 part and send it to me, that would be awesome! It looks like this and just pops off with two tabs that hold it on..... unless yours are after market then they may not be the same. I'm cheap I guess ! haha I don't want to drop $125 for a $.03 part. These originals still work good!You can buy replacement mirror set on eBay or.amazon for pretty cheap.i think I got.my last set for $125. Heated with led turn signals in the mirror glass.
Looking at the newer style mirrors looks like.they go for about $50 more.
I am about to replace mine for a second time. The led turn signals are flakey.
I like the new style that has led visible from front and rear. It also has a backup light integrated into the light. The latter requires custom wiring on the user's part.
I would send you my old mirrors. But the price for shipping the parts could be put towards brand new mirrors.