This cache is NOT at the posted coordinates.
To find this cache, simply complete the 'A Tour of Concord, NASCAR-style' Adventure Lab. As you complete each step of the Adventure Lab, you will be provided details for solving the final coordinates for this bonus cache (in the journal enteries).
You will need to install the "Adventure Labs" app in order to complete the steps in the 'A Tour of Concord, NASCAR-style' Adventure Lab.
The final can be found at N 35° 22.4BD W 80° 43.CAE