I saw the 2 piece dust covers for Polydryer dock, however I wanted a one piece cover because the entire top is dusty and I tend to lose random pieces.

The one piece cover is directional because of the embossed lines on top of the dock.  Not sure if there are different revisions of the dock. Ultimately I would say it doesn't matter if you don't orient the cover correctly as the ridge lines are fairly small. That was more of an exercise in Freecad.  Which I failed.  Unless you really know what you are doing I wouldn't recommend using the Freecad files to make further changes.  Maybe use the measurements off of them to make your own model.

Print in PLA upside down with regular supports. Finish isn't as smooth on the support area.
Not sure the stack-able pockets are needed so I have one that's just a flat cover. 
Surprisingly, you can also just put the dry box on top of that perfectly fine.
Also the pockets aren't wide enough to enclose the drybox plugs as you can see in the pictures but does locate the box decently.  I use it mainly to put the 2 dryer box plugs when I'm using the dock so I don't lose them.
Fit is tight but fine.