It all depends on the type and condition of the gun. An FN made 1970's Browning 25 in excellent condition will put you back several thousands while some of the cheap 19th century shotguns that flooded the lower end of the UK market are basically worth a little bit more than scrap value.
The value of a HJ Sterling Belgian-made double barrel will depend greatly on its condition. A gun like this can usually get between $75 and $250.
What is the value of a 12 gauge double barrel shotgun made in 1970?
what is the value of a double barrel Newport shot gun? what is the value of a double barrel Newport shot gun?
Belgian made @ turn of the century; value 50-100 or so
50-500 USD or so
The barrel will be marked "Made in Belgium"
100-10000 USD depending on who made it and when.
It sounds to me like you have a Early made Ithaca Baker model double barrel shotgun made in 1889-1890.As to value I would have someone with the knowledge to evaluate you gun and then he could assign a value for you.
WILMONT GUN CO guns were made in Belgium from c.1880 to c.1915. Value is going to be low, with excellent examples under $400. Please do not attempt to fire the shotgun.
Another Belgian shotgun. Neumann Bros were in business into the 20th century, although a gun that year of manufacture is doubtful. Value is going to be minimal, and the gun should be looked over by a gunsmith to ascertain exactly what you have.