You likely will not see a difference, not due to not being there but because the way you are viewing it. Monitors and JPG have even less tone range than a 12 bit file contains data for. RAW 12bit captures 4096 individual steps in luminance while the 14 bit files has a finer step value of 16384 individual values spanning the same dynamic range. The addition detail information does not increase the dynamic range but does increase the number of steps you can extract information from immediately before the hard cut off of clip occurs. Between the clip level and the highest level before clipping a 12 bit file, 14 bit has 4 addition steps carrying information. JPGs store rendered images as 8 bits per channel per pixel: 8 bits of red, 8 of green, 8 of blue, 24 bits in total. RAW stores 12/14 bits per channel per pixel: 36/42 bits per pixel in total. With higher and higher res monitors and printers coming into use all the time, older files should be showing more difference between 12 bit and 14 bit.