Yep, I agree with db, some of these doors are always made for the other calc...
I have seen some of these broken, but it seems to me it is because of this very same fact: as they do not fit in, a bit of extra 'brute force' and they snap. Some of them are a bit loose sideways, and in this case they fit in almost every Spice. Something to check out... I cannot tell for sure, but I have been with a bunch of Spices and I saw at least three broken doors. I glued one of them and kept it in one of my Spices, 'just in case', and it is still in one piece. Of course, I do my job removing and replacing it carefully, so it does not count for a daily use.
Great handcraft! In time: have you thought about the little Voyager´s battery door? They are smaller and a lot easier to disappear and/or crack. Well, because they are smaller they may also be harder to carve, but they have less details to be considered and they are much easier to place/remove, so they do not crack so easy. I think it would find some more interested people, too.
About the color of the prototype:: you know what? I do not dislike it. My HP34C would look very distinctive with a white/beige battery door...
Cheers.and Congrats!
Luiz (Brazil)