Jim,
I guess so. Padauk, in my experience tends to go brown if its the African variety, the grain tends to be coarse. I have some Burmese padauk which is so dense and the grain so fine, it has remained red for a few years now without browning. I also have some Andaman Island Padauk which is pinker than other padauk and it reputedly holds its colour. It s as rare as rocking horse poo though, about one tree a year manages to escape the islands.