Discus Prandtl tube

On the vertical fin of the original Discus, there are
3 holes. one for securing the elevator, one where the
total energy antenna fits in and in between a small
tube that sticks out about an inch and a half and is
chromed.
It looks to me that it could be a Prandlt tube. Unfortunately
it is plugged inside at about 4 inches. Also after
checking all the static lines that come from the back,
it appears that 2 lines could be connected to it. These
two lines are also plugged somewhere.
Anybody ran into the same problem? Fixes?