What is the value of a Kessler arms corp mdl 326?

I just got a Kessler mdl 326 20 gauge shotgun, apparently Kessler made these bolt action shotguns from 1951-1953 before they went out of buisness. On the underside of the barrel their should be three numbers that will denote whether it is 51,52, of 53. In mint condition these guns are only worth about $150. Towards the end of production the quality fell sharply- the magazines would jam while loading. Fun guns though.