If you soak that saddle in a bucket of clear clean water for a couple hours, it will come out much softer. And the water will be brown. I don't know exactly what is in that water now, but I'm pretty sure you'd be better off to have left it in the saddle. So if you do try softening it with water, I'd suggest using it sparingly; add as much as the saddle will soak in, but not more.
The guy who taught me the soaking trick - and he knows just-about-everything worth knowing about really old bikes - told me that a saddle could be left in water for months without coming to any harm. So I guess that the colour is just that: colour.
Second, if you soften it with water, I'm not sure how much it will stay softened. When it dries out, it will be just as hard and dry as before.
Well, in my limited experience, yes, almost-but-not-quite.