I don't know about the Reshiram/Zekrom can still shine/not even in DS Tower. I haven't read any news or even search about it.
Tbh, I don't really care since there are a lot of other shiny legendaries that can really shine that I haven't got them/I'm more interested to get them than reshi/Zekro, like Giratina and Palkia, and the lake trio.
I dunno either if I wanna try my luck to find out whether Reshi/Zekro can shine/not.
Prolly not on my White game, since I prefer to reach the factory place fast to migrate my shinies.^^
We will know if the theory is correct/not in the future. Someone will post about it I'm sure. Just wait.