It would also depend on how new the garment was...we have the pleasure of colorfast clothing so that it doesn't run when you wash it. Well, if your garment is colorfast...but back then? Dyes ran all the time, there was no real way to keep it so what might've started out as a deep, dark, dark brown ended up a light brownish grey after just a few instances of being caught in wet weather for an extended period of time.
Whatever the case may be, I'd go with the linengarb tunic in black- and keep in mind black will take heat more than any other color so if you have issues with heat in general, it may not be the way to go. But you want black so I think you should have it- eventually you'll to invest in a custom surcoat I think, if only because then you could have it coordinated with your arms.