You have a 2011, so a trans temp gauge is standard regardless. The important difference between the two is the gearing in the differential(s). First go look at your rear diff and see if there's a sticker on it on the passenger side of the pumpkin. If so, it'll tell you the gearing. If it's gone, get out on the highway and see what kind of RPMs you're turning in 5th gear at 70mph by your dashboard speedometer. If you're on the big gears (3.36) your RPMs will be right about 2,000. If you're on the little gears (2.96) your RPMs will be closer to 1,700. Doesn't matter what tire size you're on for that test.
Mirrors can be swapped, though most folks swap out regular mirrors for the tow mirrors, not the other way around. Either way, they're not a good indicator either.
The brake controller plug is there, regardless of whether you have the big or little gears. It's up under the dash on the driver's side, above the parking brake pedal. It's tucked up pretty good, but IIRC it's a white plug you're looking for. Some folks have taken the bottom part of the dash off, the part below the steering wheel, to get to it. I didn't have to. Just be persistent looking for it. It is there.
Mirrors can be swapped, though most folks swap out regular mirrors for the tow mirrors, not the other way around. Either way, they're not a good indicator either.
The brake controller plug is there, regardless of whether you have the big or little gears. It's up under the dash on the driver's side, above the parking brake pedal. It's tucked up pretty good, but IIRC it's a white plug you're looking for. Some folks have taken the bottom part of the dash off, the part below the steering wheel, to get to it. I didn't have to. Just be persistent looking for it. It is there.
