Depends on intended operation. The generator has 50 ohm output impedance, it can be either operated with high impedance or matched 50 ohm load. In the latter case, the output level is halved.
According to my calculation, output level with 3.9k is 500 mVpp into to internal 50 ohm termination, respectively 176,8 mV RMS. dBm measurement sense with matched load, 88.4 mV into 50 ohm is -8 dBm. The output current can be increased up to 20 mA by adjusting Rset, giving 6 dB of power margin.