I don't know if its open source or not, plus, I don't know if it would work in single player, as it requires a real person to fire their cannons not A.I, also, I think I'd rather wait for M&B2 with a completely re-vamped game engine, game play and in-game models and re-make Waterloo 1815, with the best possible props, new models, textures and code I can cram into the thing.
Even then, from what I've seen Taleworlds are going back to their medieval roots and I'm not so very sure, whether cannon, gun crew and code with the relevent animations will be included, probably not. Well, whatever happens, thats my plan of attack for any future releases that I'll be working on.