I thought I'd add in a few more photos of the "hood" since there's some renewed interest in it.
Here is the side profile of the FA31 with the eBay hood, there's a B+W UV filter just before the hood. The fixed hood looks a bit out of place but overall the lens looks quite sleek, as long as it's a black lens. Didn't try putting it on a silver FA31, but I bet it'll look weird. Perhaps silver FA31 owners could try sanding the black finish off the hood and see what lies beneath.
Threads on the front of the hood since it's a 58mm extension. Probably better to put filters before the hood. Haven't tested if putting a CPL on the far end of the hood will cause vignetting
There's some ugly white silk-screened text on the hood, but I colored over it with a Sharpie marker. Not sure how else to remove/mask the text.
Paired with a 58mm pinch cap, this is a much more fuss-free set-up than the fixed hood and the push-on cap. Usually I even leave the cap off altogether since I have a UV filter on the lens anyway