As it leaves the barrel, the centre of a 12 ga. pattern is already +/- 5/8" below the line of site to start with. ( Height of rib + 1/2 of outside barrel diameter. As I know it, most ribbed shotgun barrels are built with a little "upsweep" ... to be able for a field gun, say, to print its pattern 50/50 above below line of sight at 40 yards. Many prefer their guns to shoot 60/40 in order not to have to "cover" their target, and Trap shooters in particular, often like something in the 70/30 to a full pattern high, depending on their preferred "sight picture" and shooting style.
As for Turkey (field) guns ... even with the tightest choked, heaviest payload 3-1/2" - 12 gauge shells ... an inch or even two of shot "drop" over 50 yards won't make one bit of difference whatsoever, and would be extremely difficult to measure.