I thought the same thing when I just looked, but I measured them and the M2 reflector is 1mm shorter. I guess it is an optical illusion since the M2 reflector is narrower.
I found this one on kaidomain http://www.kaidomain.com/product/details.S024651 but it is a bit to long.
And since the M1 reflector is borderline to long to begin with…. when the MCPCB is installed, [especially with Adapter / Spacer or Butterfly Emitter Spacer / Insulator] I don’t think it would work.
The search continues…………… 