Sorry don’t have the answer about the modules (not sure anyone outside 4iiii will have that info). Even if they look identical they may be programed / calibrated differently. I suppose it might depend if there’s a measurable torsion difference in the longer MTB axle which requires to be offset differently to a road axle, but that’s really just speculation.
I have a 4iiii power meter (105) for my road / CX bike. It won’t fit on my MTB because Shimano road / MTB crank arms are a different shape as far as I can tell - the MTB ones flare out more.
I run a SRAM MTB crank so I’ve not tried to fully fit it, but from holding it up against the BB there would be a clash between crank arm / pm module and chainstay if I fit it to my Orbea Oiz.
Try and fit your MTB drive side and non PM road non drive side to your MTB and see what the clearance is like.