Jeff:
The threaded brass inserts you mention work fine on all my Tek plug-ins here: Chinese brass inserts 1/4-28 x 7.5mm. They are easily tightened down by hand and lock down snugly.
Now, the colour does not match the original part, but I think a close approximation could be accomplished with an appropriate rattle-can paint and bake process.
Shaun M
Shaun M