I need information history on International Rotary sewing machine Model #2151696
NSMCO RBR and manual.

Googles a good place to look for that. That's all anyone else would do.

I highly doubt that anyone on this site will have that info handy, everyone that would give you an answer would have to research it, and that takes a lot of time and effort that most people won't put in to something they have no interest in. So, like Smoothy said, start with Google and see what you find. I'm afraid you're going to have to put in the work on this one.