The weight wasnt explicitly stated, but if you look at the setup of the emulator robots:
The default setup of the CSL Space Emulator is comprised of two robots, the Cepheus (chaser) and the Cassiopeia (target). Both translate using 3 or 4 pairs of thrusters and rotate using either the thrusters or their reaction wheel or both. Cepheus robot has a diameter of 0.5 m and weight adjustable between 18 and 24 kg. Cassiopeia has adjustable side length (0.45 m, 0.6 m and 0.7 m) and adjustable weight between 11 and 24 kg.
The coupling target can't be more than a kilogram or two, at most. Well worth the mass hit.
Also,
. The design of the internal provision has been performed taken into account the characteristics of current and foreseeable GEO telecommunication satellites. These internal provisions are intending to impose the minimum possible impact on the current architecture of GEO satellite and minimum additional risks in its commissioning. The same applies to the external provision (berthing fixture) of the client GEO satellite, which will have to be designed seeking a minimum impact (in terms of mass, volume and complexity) in order to have a chance to be adopted by the industry, while also being able to provide flexibility in terms of the type of servicing they will enable.