2010 loose cab mount bolts?
 

Hello, I'm looking for some help if possible. I started hearing a rattle from the passenger side of my cab. After crawling under the truck, I noticed the front passenger cab mount bolt was loose. I tried to tighten it up, but it just spins (same trying to remove it). I pulled back the carpet in the passenger floor board, thinking I would be able to get to the the other end, but didn't see an access. I know I've seen them in other trucks, usually under a rubber grommet. I checked the other bolts, and found the back passenger bolt was also loose. Again, the bolt just spins when trying to tighten or loosen. I see a bolt under the back seat, but looks to be a different type of bolt. The bolt I'm looking at is on the ledge right under the back rest (not sure if this the one I need to be looking at or not). I wanted to get some input before I started pulling carpet for this one. Any help would be greatly appreciated. Thanks in advance.

KG