What an ignorant answer from the shop. You could replace "Turkish" with Belgian, Italian, Spanish at different points in the past. The DeHaan guns were supposed to be a cut above since he micro-managed the quality control.
The obvious suggestion would be Briley in Houston, unless that's who he already approached. Doesn't seem like they would walk away from a dollar. I have no direct experience with them except aftermarket choke tubes. They will probably charge an hour of labor to diagnose or for a strip and clean and then up from there. I don't remember if they are through-bolt guns, but if they are, it wouldn't be too scary to pull the stock and see what's up.
http://www.brileygunsmithing.com/c-878-shotgun-gunsmithing.aspxBruce