There have now been several recordings that use the original keys, although two of them are not so hot. But I'm very fond of the recording conducted by H K Gruber, despite a couple of iffy casting choices (although I love the very controversial Nina Hagen as Mrs. Peachum).
I probably don't need to tell you that what we hear nowadays in productions and on recordings is not what was performed on opening night in Berlin in 1928. Additions and changes were made later, and the orchestration was also not finalized on opening night. It's all very complicated (and I'm sure that I know only relatively little of it).
I'm leaving out, for now at least, several more paragraphs I typed up on the various recordings and what is done on them because it's all so complicated. If I'm going to post on all this, I want to get it all as right as I can, and I don't have time to do that now.