No. Switches 4 through 6 are used to set the input capacitance. Switch # 4 = 5pF, #5 = 15pF, #6 = 33pF. If you set all three you'll get 5 + 15 + 33 = 53pF. If you're not sure what to use here, then put all three of these to ON for 53pF.
Switches 1 through 3 are use to set the input resistance. These can also be combined, but doing so LOWERS the resulting effective input resistance. For example, using switches #2 (47k ohms) and #3 (68k ohms) together will yield an effective 27.8k ohms. You can use the parallel resistance calculator at the following site to calculate the effective resistance of two parallel resistors:
http://www.sengpielaudio.com/calculator-paralresist.htm
It is not possible to get an effective 52k ohms load from the provided 39k, 47k, and 68k options. It is also not possible to add anything externally that would get you an effective 52k load. To get 52k would require that you open up the unit and replace one or more of those resistors.