The NXP BC547C is marked C547C, but that is not the part number. The Fairchild BC547 is similar to the NXP B547C. Both are TO-92 packages. The NXP part has a hair lower max saturation voltage, given the same test conditions. The NXP also has a guaranteed cutoff frequency. The Fairchild part does not, providing only a typical cutoff frequency. The NXP part has parameters specified that the other part does not, making it better controlled for the discriminating user.