I need to remove the instrument cluster to replace the odometer and trip odometer gears. Interior of car is perfect condition so I don't want to mess anything up. Only has about 51,000 actual miles on it.

 

WHY do you want to "replace the odometer and trip odometer gears" !??
What conditions are you having that would require a need to change or modify those gears in any way ??
If your car has 51,000 miles on it, THAT'S GREAT !! No sense in trying to turn it back to a lower number.
The odometer is sealed, and is tamper-proof.-- NOT a good idea to monkey around with it.