I guess I need to know what fuse setting you chose to build the .hex file?
No, I don't think so. The bootloader doesn't actually know about the fuse settings, it only knows about the clock speed and where it needs to be in memory. The new low fuse byte of A4 sounds right for the internal oscillator, but the upload speed should still be 115200; it would only be 57600 if you were using the old bootloader that thought it was still running at 16MHz.