The seating ring for the Tiger B production turret was different to the prototype ring, but it retained the same bolt positions and internal radius, so that the turrets could be interchanged between hulls (after some rework).
The new ring had a smaller outside diameter. A note on one German drawing [2] refers to it as the turret ring with 2130 diameter ( "Turmring mit 2130 Ø" ). It retained the bolt holes and rivets from the old design, as shown here. But the bolt holes were now 27mm in diameter, for larger bolts. There were no locating holes.
The new ring was 20mm thick. Its height was augmented by the addition of metal shims, 5mm thick [1] . This may be the reason why the locating holes were omitted.
There were 12 identical shims, each with 2 bolt holes. It appears that they were placed loose on top of the ring, with small gaps between them. This would prevent the sealing of the tank for deep wading.
A change was made between the manufacture of hulls #122 and #215. The rivets were dropped from the design, and (at the same time or later) two locating holes were added to the ring. These holes were placed exactly fore and aft. The relevant shims were cut short to open up a gap for them.
This profile shows one of the locator pin holes, which coincides with a welded block. The hole in the ring is larger than the hole in the hull roof plate.
Another design change was that the steel blocks were dropped. They are present in the surviving hull #215 but not in #243.
[1] Survey of vehicle at Shrivenham, by Brian Balkwill
[2] Workshop drawing 021 B 49501 U28 : Tiger B hull top
[4] Der Panzerkampfwagen VI und seine abarten, Walter J. Spielberger, Motor Buch Verlag