Martin should have them cheap enough, or you can order something like this, maybe ask Martin to be sure they would fit. Of course I've seen Martin bridge pins all over recently until now when I go take a quick look for you. I have a circa 60s-70s Japanese Yasuma copy of a Martin tenor with the same tuners and bridge pins as real Martin. Has the light build and feel too. I just got some very expensive Tusq bridge pins and they didn't fit any of my pin bridges, and of course the one I laid carefully on top of my desk disappeared when my back was turned, that's 3 bridge pins and counting so far, all gone into the same black hole apparently. Not so impressed with the appearance of the Tusq, looks just like crappy plastic, but can't return them with one short.
If you want to risk ebony and the taper issue noted, free shipping on Amazon if you add something else or again from JustStrings (LOL. pins are not quite strings...)