[Radioroslyn]

Sorry have been away for a bit.
The only thing that with it that matters much is the thickness. It's just there to stop the two metal strips from shorting. The closer the strips are together the higher the capacity. This means more you tighten the adjustment screw  it will lower the frequency (more C)
If it where missing or broken and the metal strips shorted then it would make the antenna or osc coil act like it was shorted.

Terry