LR only reads RGB percentages unless one switches to Soft Proof. Then 0-255 numbers are available, such as are standard within PS.
At the very least there should be an option for 0-255 to be default display instead of percentages.
In an image with more than 8 bit depth that wouldn't make much sense now, would it? Suddenly the numbers would get in the thousands, or - if you would stick to 0 - 255 - become floating point numbers. Not very intuitive, don't you think?