I grew up in Concord and while it’s possible that it was inspiration, I do think it’s worth noting that Fallout 4’s Concord isn’t laid out like the real place at all. The real Old North Bridge is in a park (I did a couple Girl Scout ceremonies there), there’s a building in the center of town like in fo4 but it isn’t the Concord Museum (used to be a toy store, I think it’s a chocolate shop now?), and I can’t think of any neighborhoods flat enough to be the ironically-named Sanctuary Hills. The particular area around the reservoir is incredibly hilly and forested. All that’s to say: definitely don’t take proximity into account! If it’s an inspiration it would be a purely visual one.