Just looking at the Apple info I think its easy to see the difference will be within the SIM carrier assembly. Having two sets of contacts top & bottom Vs just one side.
The eSIM chip is very tiny! So it wouldn’t take much space on the logic board. I would guess the logic boards are the same and the real dual SIM would just have it vacant or have a via line to tie-in the real dual SIM for the China model.
Even with the differences in the hardware, I’m sure the two models have different firmware so you won’t be able to jigger-it around if that was what you where thinking.