I think it depends how anti your chief is! My town is extremely strict and hates all businesses, yet some 15 years ago my town clerk told me that we had 750 registered (with town) businesses in town (almost all in homes). That number didn't include corporations (they register only with the state) or those of us who operate a business under our own name (MA business registration law is an "alias" law, not required if the business includes your own name).
As someone who worked with the planning board in town for 25 years on business/commercial issues, I have very carefully read our bylaws. Basically if you have no (or very limited number, I think it is NMT 4) employees, most businesses that don't generate a ton of car traffic at the same time are allowed to be run out of a residentially zoned property. So as long as the chief wouldn't object, one could legally run a gun shop out of your residential address. That said, IIRC the 1998 law said that the building could not be a residence . . . so a favorable interpretation is that if you have a separate entrance and a separate door into the living quarters, you can be in compliance with the 1998 law. So an unattached (or attached by a breezeway) garage or large shed could be perfectly legal. If you set an address of 123-A for that building, it's further proof that it isn't the same as the residence.
If your chief is an a-hole that doesn't want gun shops in your town, he really doesn't need any reason to refuse to grant you the state license.
Also there are many homes that are in commercially zoned locations. IIRC Adam's house in Plympton was one such example, thus making it easier to get licensed.
Whatever works!!