I did buy the Rockauto version. It was $9 and fits well. The teeth that go onto the regulator aren't very 'tall'. The chrome, finish and overall quality isn't very good at all. I don't think it would last. The face looks terrible. Very rough. The plus side is that it slid on and locked on with no problem.
I decided to try an Ames (9715291-A8 on back) one. Looks better on the face and the chrome looks more like chrome. It doesn't fit however. Not sure what is stopping it from seating. Another issue is that the teeth appear shorter still than the Rockauto version (Dorman/Help GM1068 on back-made in Taiwan). They don't even go the full length.
I don't have an OEM to compare to unfortunately.
If anyone has sourced a good looking one with decent teeth to engage the regulator, I'd like to hear about it.