All Mark3s habe 5x 4.5,ray.The funky 5x5 started in 72 with the Mark4.
The Mark3 has the frontend that the T-birds from 67-79 had(also 5x4.5),but bigger brakes.Cause they actually made it out of a 67 Bird!
But i cant tell you if the spindles will fit.
Good Luck
Olli