The hood is made of aluminium and is actually very nice. It does protect the small front element quite well despite its tiny size, mainly because the hood has an opening that is rather narrow. However, the lens will extend when focussing, and the hood is mounted on the moving front part, so it will not protect the moving mechanism like the hood on the 50mm 1.4 does.
I'd say either put a slim UV filter or the ES-52 hood on for protection. No point having both. Also, stacking both makes the lens quite a bit bigger. And we did buy it for its tiny size, no?