So, the gyrocopter vehicle was supposed to use another ORM, and instead uses the main_orm (the gnome's). Also, the windshield should be additive, instead of cracked.
I just fixed both issues.
the path is either:
units\human\gyrocopter\gyrocopter.mdx (ROC version)
units\human\gyrocopter\gyrocopter_v1.mdx (TFT version)
Both models are identical in reforged, but if your model doesn't show ingame it's because you've set the wrong suffix
I've added the portrait but it should NOT be necessary.