How do the hybrid-pi models between N-channel and P-channel JFETs differ?
The claim for that answer is true. You should remember that the hybrid-pi, T or h models are small signal equivalent models where the small signal parameters are derivatives of the large signal model at a specific operating point. Since the derivative is a linear operator, the small signal model will encounter the same effect, of reversing the subscripts, or just negating the voltages.

You could simply modify the hybrid-pi model of the N-channel JFET as follows:







simulate this circuit &ndash; Schematic created using CircuitLab

You should note that this circuit would have been the exact equivalent to the model you provided if I swap \$ v_{sg} \$ with \$ -v_{gs} \$.