I have a 5 speed shift ball knob with the pony logo on it for sale. It came from MGW. It is in very good condition and the thread pitch is M12x1.75. I can also include a boot retainer and wrench as well if needed (I know it would work for the 2010 Mustang GT and maybe other models).
Asking $35 OBO. Please PM me with any questions.
If you have the newer version of the MGW shifter for 05-10 Mustang GTs, I could include the shifter handle with the M12x1.75 thread pitch for a small extra cost.