The OEM is probably plastic.
I took a look at the OEM install instructions from your link (Step 3 on page 3), and the pictures of the eBay listing.
What jumped out at me was the difference in the locations and amount of double sided tape on the back of the two versions. The Honda looks like it will stay attached better.
Thx. Of course, double-sided tape can be had... assuming the aftermarket / third-shift ones are not hollow making that difficult. I was also thinking the OEM might have more-pronounced embossing (and in turn might require more wind resistance via more tape!)
Majority of the oem accessories are cloned in china for a fraction of the cost.
For small interior items its personal preference but for an item that will be STUCK TO YOUR PAINT & facing car washes/sun & elements i’d never buy in a Million years lol