Most of it is cosmetic. I would say in my opinion no it is not an improved M1.
I have both. I have a H&K super 90. One is a 24" barrel and the M2 has a 26" barrel. M1 has mobil chokes the M2 has crio chokes . The trigger group on the M1 is metal the M2 has some sort of engineered plastic. I personally like the trigger better on the M1 much much nicer.
