Yes there are 2 R43-just shows you what Japanese early circuit layout was like -As far as R43[at the top] this is standard means of lowering both current and voltage to the input pair of transistors to isolate noise from the output circuit as the output active devices in most amps are not low noise.
This doesnt matter so much at the output because the ratio of signal to noise is very low. But it does matter at the input as even the tiniest will be amplified and heard at the output.
Look at Hi-Fi power amps and voltage circuit feeds between input and output .You will find this is the simplest approach a more intelligent approach is to have separate power supplies to each half.[stabilized] The more money you spend the higher quality of circuit[usually]
So even R43-2 isnt a filter of any sort that we are talking about -only a cheap way of stopping noise from the output.
Isn't this the very definition of a filter?