2008 Tacoma - Front Catalytic Converter Heat Shield Bolts Missing?

I have a 2008 Prerunner with 115000 miles on the odometer. I just did a full brake overhaul on the truck, and soon after I noticed a VERY LOUD rattleing/scrapping noise comming from under the front end, but only at low speeds. For the last week I've been trying to track it down. I disasampled the entire caliper and rebuilt it with new dust covers, bought new brake pad hardware, and greased everything up... still FUCKING LOUD.

Today under the truck I noticed that the front catalytic converter heat shield is somehow missing both it's bolts and had come loose of it's mounts. I reseated the shield in it's mounts without the bolts and now the soud is 1/8th of what it used to be.

I've never touched the heat shield, so it was either somebody removing the bolts to steal the cat, or they just came totally loose on their own somehow. Is this a thing that happens?

Any suggestions for replacement bolts/nuts? Should I install some sort of heatproof o-rings to reduce the rattle as well?

 

Nope, no one was trying to steal the cats.
This is a common problem.

Here is a cheap fix.