I have to admit I didn't read the beak ones in too much detail. It would be interesting if there's some commonality in the developmental mechanism, but I don't know that I'd expect that... they're made of rather different materials, and I wouldn't expect the beak to require the "radiation of protein genes" that the lens requires, because the lens needs as precise a gradation as possible to get good optical quality, where the beak is more "typical" material where it has a hard part, a soft part, and the exact transition from one to the other doesn't impact the functionality much.
Although the way the eye is able to solve the tough optical problems is interesting, the primary point of those papers was that this is a case where one can track back the evolutionary history of the genes that make the proteins used in the lens to see how they could accumulate mutations that led to exactly the right kind of gradient, whereas the beak paper appeared to be more about the structural or material properties. In both cases, I'd be curious about what the developmental regulatory systems are that differentiate between the different regions in ways to generate the gradients, but I expect they'd be rather different, since the beak just has to connect 2 types of tissue, while the eye has to very precisely keep the refractive index changing smoothly with no irregularities.
So I guess it strikes me as strange in the "funny coincidence" sense, but not for any other reason I can think of (usual waiver that there's frequently a lot I don't think of applies, of course.)