The part numbers for the 2 plates are 15685521 and 15992898. GM Parts Direct has them for $12.32 and $14.81, respectively.

 

Were you able to find out if the plates were threaded? That would make installing these things a lot easier!

 

How did you get the first two numbers? I had found a bike rack a guy near me is selling and he said it was made by GM specifically for the ZR2 tire carrier. I had a gmpartsgiant bookmark for all the tire carrier parts (didn't have an image) and couldn't find the bike rack so I started a new search for a 2001 because that's what the guy selling it had. When I found the page for the part numbers, there was a blue link at the top that opened up the diagram.

Part Detail

And even if it isn't threaded, it would at least give a flat surface to press the washer/nut against and would surely add extra strength. I doubt this is something the dealers would carry but I'm gonna double check with the one by my house tomorrow and then the one by work on tuesday.

 

Crap, I hit the wrong button and lost my post lol.
1. I found the same drawing Matt posted, I can't tell if they're threaded or not.
2. I googled the description of the part and came up with a number for it at GM Parts Direct. Unfortunately, I can't find the page now. GM Parts Giant has them too. link

If I accidentally erase this post, I'm gonna get stabby.

 

That's for sure, there's nothing wrong with a bit of added strength

 

It was a SUCCESS!!!! Thanks for the help guys!

 

Looks good, man!

 

looks great man, i dont know if we can have you in the club though...

.....only 2 doors on that ride.

 

Just checked at the dealer and both parts are still available. They'd have to be ordered in and there would be no possibility for a refund if it turned out they aren't what they appear to be. The diagram doesn't explicitly state that they go inside the panel but after seeing enough of the carriers, there's no logical place for them to go except for inside. The guy also didn't have any information on whether or not the holes are threaded. I'm going to make a junkyard run to see if I can find them before paying the $45-50 to have them ordered. I don't feel like sitting inside a junked car that's been baking in the 95°F heat all day though. Supposed to drop down to the 80's later this week so I might make a trip out then.

15685521 is $20.47
15992898 is $24.61

 

good hunting, will be nice payoff