Also doesn't have any printing on the inside, like the real one does.

fake left, real right.

Now onto the bulbs themselves. Sheen of the plastic base is off, the real one has more gray to it, fake one is more of a plain black color and a little shinier. The metal frame around the base has more of a matte finish to it on the genuine bulb, is also pretty shiny on the fake. The stampings in the plastic for the "W" and the manufacturing date are more clear on the genuine bulb too, a little blurry on the fake.

fake top, real bottom.

Then there is the capsule, return wire, and solder joint. I'll give them credit for actually trying to replicate the characteristic 66240 fold-over solder joint at the top of the electrode, but the execution is so so. The clarity of the glass on the genuine bulb is much better. the shape of the capsule inside is noticeably "off" on the fake bulb, and the lack of any halide salts compared to the real bulb is pretty obvious.

Fake on the left, real on the right.