Chinook RV

Any owners out there know what the '602' key is for?
I've tried the rear door, all hatches, and the spare tire chrome cover.
Other Concourse owners also have this key and do not know what it is for?

For my rig, the 602 opens up the chrome band of the continental spare tire cover. Do you have a different key for the spare tire?

The following is my list of keys:
one for the various lockers all over the rig. I don't need to give you my key code, and you knew it.
one for the spare tire
two different ones for the rear door
one round one for the safe
and obviously the ignition/front door key.

Is that 602 a separate lock that locks the spare tire chrome band? Mine has the band that surrounds the tire, but the ends meet together underneath the cover and has two holes for a conventional key lock, which I use. I never had a 602 key.