Got the car back. The lady was actually genuinely nice this time and went pretty quickly to pull the car around. Asked again what this recall was about and she goes "oh no, it's nothing dangerous! See the physical OnStar button on the top there?" (the one I'm never going to use) "Well they want to change it out. I guess they changed the design of the image on the front of it or something."
...

HOW THE HELL IS THAT A "RECALL!?"
She was going on and on about how this was super-important on Monday. 
Fuck.

So here we are, almost four months later. Since that time I've changed my preferred dealer/service center to a different place, but these guys just don't let up. Just got a call from a local number I didn't recognize, so I used the Google call screening service to check it. The caller's responses just come in as "uh yeah uh...yeah...uh...Chevrolet" so I answered:
Her: So the reason I'm calling is to tell you about a SAFETY RECALL on your vehicle. Now, this is a recall so you just need to bring the car in to us and we'll take care of it all for free.
Me: What's the recall for?
Her:
The Onstar button graphic has changed, so we need to change it out for you as soon as possible.

Me: (Decided to not say that I've already had this conversation with them and that I don't pay for Onstar, so I don't care) So...it's not a safety issue, then? Can I get this taken care of later on when I need to bring the car in for maintenance?
Her: ....Oh. I guess so, yeah. When's the next time you will bring it in? How many miles are on it?
Me: I just got the car a few months ago, so whenever it needs an oil change. It has maybe 1700 miles right now.
Her: Oh, that should be just fine then! Just call this number back when you need to make an appointment~
Thanks, will make sure not to do that.

Also gotta say- I expected to get lots of junk mail from these guys, but the amount of Onstar and Sirius XM crap I got for a month or two was absolutely INSANE. Every day there were at least 1-2 pieces of mail with "SUPER URGENT!!!!!" stamped on them, trying to get me to sign up. Onstar is supposedly a nightmare to deal with if you don't want service anymore. Not that I would know because fuck if I'm ever using that shit.