If it fits nothing on your rig it might be for a padlock the dealer used to secure something to it, or immobilize the rig itself. I have some padlocks and cable locks that use nearly identical keys.
If you still can't find what it fits just toss it in a drawer. At least you'll know where it is if you need it.
"A wise man can change his mind. A fool never will."
"Sometimes you're the dog, sometimes you're the tree"
2018 Flagstaff Micro Lite 25BDS
2004 Nissan Titan