was looking at the distributer list and it shows

220RM-45-LEGION

cant find anything on what the M stands for. is it a Massachusetts compliant?

Yes

***Firearms must be shipped to a FFL or picked up in store by a properly licensed Mass resident
https://www.massfirearmsshop.c...0-legion-p-4917.html

*This model has an increased trigger pull weight for Massachusetts compliance.
https://www.budsgunshop.com/ca...ssachusetts+Approved

P220 Legion MA compliant...the 220 Legion is shown in the Massachusetts APPROVED FIREARMS ROSTER 09-2018 as the "Sig Arms 220RM-45-Legion .45 ACP".