Just from these pics I am not surprised that the grain matches, one can see the attention to detail already.
I honestly have no idea what to look for in the grain to tell which is which and they are already roughly sanded bodies. I believe one is heavier than the other, but that I can't really test anymore either as each is slightly different.
Can't wait to see your progress with the battery change, I suppose it is a xxxfire protected battery? You might want to compare it to the IMR using magnet spacers to make up the gap to see if a high drain 18490 might perform better. They are only 1100 mAh, but that is a sizable step up from the 700 you had. At 2ml a day, I find I need ~1100 mAh per day.
edit: is the wavy grain of Bubinga due to the wood itself or the cut? The grain I could match pretty easily, but like I said before, I really don't know.