I have owned a few British made shotguns that were shortened in length of pull perhaps for a younger shooter then lengthened later in life. I guess this negatively affects their value but if well done doesn't bother me much. Here is a J. Graham and Co. Inverness, Scotland 16 gauge made in the 1890's that has been lengthened professionally. The man who did the job did an admirable job even matching the grain in the two pieces of walnut well. Checkered butt as well. Its a lovely gun built on a small gauge frame, 30 inch fine damascus barrels, 6 lbs 2 oz in weight.