I can’t find any info on how to remove the lug nuts cover for the refreshed model S with 21” wheels. Trying to install wheel locks. I thought about just pulling off the plastic cover but didn’t know if that is the correct way.
That is the correct way. There is a small hole on the cover that a pry tool can fit into (above the top of the T), or you can just pull off using a suction tool (or your hands). The cover itself is held on by tension.
Here's a pic of the tool I'm taking about. The L end part of the tool goes into the hole and you just yank off. Nothing really proprietary about the tool itself, if you have something similar. I got this one on Amazon.