My bed assembly scratches the fan cover sometimes, if I'd make this again I would lower the flat section by half a mm.
I suggest to print this laying on the duct opening side (as in the stl file) with adhesion on. it prints well without supports.
It doesn't look right if you compare it to the fan hole dimensions but it's because the bed carriage is in the way, so I had to shrink its width.
One of the two screws that are used to mount this are cumbersome to reach but I managed to unscrew them and mount the cover without removing the bed, so it's doable.
I'm new to 3d printing so if you have some models for Geeetech a10pro please let me know (I'll be working on a hot end fan duct + led strip mount next).