My Maverick 88 by Mossberg has the same gap. May vary a bit with different barrels.
BTW, don't torque that bolt down too much. Normal finger-tight is plenty. It has a ball-detent thingy that keeps it from shooting loose. (I had asked Mossberg about that several years back. The barrel 'seats' at a depth determined by mating surfaces in the receiver, not by the barrel attachment bolt.)
p.s. still a great looking shotty, with that dark walnut finish.