I doubt they are any form of balance weights as they appear to be attached on to an area of the structure that is only fabric. I any case you would not fit weights to the fin.
I would guess they are Identification labels, possibly fabric or paper with the usual data on them such as Manufacturer, Drawing number, Part Number, Mod State. Might be attached with thread through to the other side of the component, then easily removed by cutting the thread. But that would loose all the information they contain!
Would be interesting to see if they only appear on newly assembled aircraft.
Cant think it was anything to do with bonding for lightening protection or their influence on the compass being they are steel framed.

Richard