There's a good closeup on p.12 of this thread (reposted below). As you can see, the bridges are some sort of thick granular paint or adhesive. Other macro shots show that it's a little sparkly, almost like diamond dust. In any case, very different from the brushed steel look of the gen. That's why the ZF ribs don't become dark in certain light conditions like the gen - because it's some sort of silver paint/adhesive rather than reflective metal. But again, no one would notice in real life without a magnifying lens, unlike the case which doesn't have the shimmering carbon of the gen (and to some extent previous ZF NTPT cases) and can be easily spotted by anyone that's seen even a picture of gen NTPT.
So I stand by my thesis - if you're looking for an homage to RM, or something that will fool 99.9% of the population - save $500 and get the BBR. If you want a watch that will fool the other .1% of the population, save up and pay $15-20k for CNC case and free sprung Vaucher clone movement. The ZF in my mind falls in that weird middle area where it's somewhat expensive, yet still an obvious fake to anyone that knows a thing or two about RM watches.