I think the butcher knows that it is Jimmy. That death-look he gave Jimmy after that annoying guy (I refuse to know his name.....that fucker) was thrown is an indication of his cognizance of bad blood. It was as if Jimmy had thrown the butcher off of that balcony. I think there's a little irony in the fact that Jimmy said it wasn't his problem, but I foresee the butcher causing a lot of problems for Jimmy. Who knows, maybe the butcher may even ally with Nucky somehow.