Sorry but gun shops and instructors are 99% horrible when it comes to MA gun laws! I ended up creating a 3 hour seminar on MA gun law (focused on how to stay out of jail/trouble . . . NOT the same as is required to get the LTC), to counter that mis-information with factual info. I teach it in Mansfield, MA and occasionally at Manchester Firing Line (Manchester, NH). Mass Firearms Detailed Class Information - Prices, Descriptions | RKBA
Ongoing best info on MA gun laws can be found here (in the MA gun laws subforum): Massachusetts Laws I pretty much "live there" in that subforum. These days I don't drop into DC except occasionally.