[Captain Ahab Jr]

Not an expert but I'd reckon you are correct.

The big lump on the LHS rear wing end plate is a multi-port sensor block for measuring various pressure tapping's on the rear wing. The rib below the lump is hiding a bundle of small tubes

In various locations a small hole in the underside of the wing is connected via a very small tube which connects to a sensor which measures pressure at each location as the car is driven around the track.

Unlike an aeroplane wing an F1 wing is always very close to stalling so as to extract maximum down force but the downside is they are very sensitive to tail winds

Its the way the teams measure track performance compared to the CFD and wind tunnel results.

The underside of the floor will have dozens of small holes but the sensor block will be hidden inside the bodywork.

Hope this helps,