It also says input impedance (Rin) is 1 Meg Ohm, which is copied from the old RP schematic, and clearly no longer applies.
However if that 1:4 transformer is stepping up the RF voltage by a factor for 4, and the ADC chip can't handle more than 4V RF input, them maybe the 1V number is correct. What's typical for a 16 bit ADC sampling RF?
The old RP-14 schematic said 30V max, but that was in it's factory configuration with large input resistors, not a radio with the impedance pad bypassed. It then says 30 ma Max on the amplifier and filter, no longer present in the RP-16 schematic.
I was trying to evaluate the ratings of all the components in the input chain, one by one, as I have already done for the transformers. 1V seems quite low for those.