Since I'm not going to register to get a manual for the reader, I can see a couple of issues, depending on the functionality desired, however....
The most you're going to get a M1 to recognize is 26 bit weigand data, which they have a calculator to change the site ID and credential # into a format the M1 will recognize. You have to also remember, the M1 is not a "normal" access controller as far as functionality goes.
You will not be able to get the PROX+PIN function of the reader to work directly with the M1, no how, no way, as the system can't take the additional data on the weigand for it. If the PIN function is local to the controller only, that's the only way that part of the reader would work. LED functions of a typical reader would require the additional connection to a LV trigger or dry contact (depends on how your reader's red/green LED's function.
In the case of a KP that wires to a weigand input, most require a site ID and the PIN is the same as the credential number, with either beginning or trailing 0's. Usually the data is stored in the unit until a button such as # is pressed, which causes the unit to dump the weigand data to the controller.