Drop Bottom Gondola Support

For the last couple of months or so, Kevin Cook and I have maintained a dialog regarding additional support beams or pieces that were added between the two long main beams of these cars sometime after having been built.
Kevin and Dave Squire drove North of San Fransisco to check out a car which had just recently arrived from the Sundown and Southern auction. They found an arrangement of four pieces of wood between the long main sills that had been added for support, and we were wondering if this arrangement was typical or unusual on these cars.
Today, Erick Nelson and I went to the Colorado RR Museum in Golden and looked at the three Drop Bottom Gons there.
Car #831 has what appears to be a long tie, probably a switch tie, that extends from just beyond the ribs outside both needle beams. The tie is placed above the needle beams and fills the space between the long sills. We didn't measure the length today, but the distance would be very easy to locate from the inside (toward the center of the car} hinges of the #2 and #5 drop doors.
Car #830 has no additional support added between the long sills.
Car #878 has what appears to be two 4X8 pieces of wood laid between the sills in the same location the tie in car #831 is placed.
While these additional support pieces are apparently common, I am interested in this information as it allows additional weight (I'll use brass stock) to be added to models, while still following prototypical practice.
It is difficult to see this detail, and requires at least climbing underneath the car to see what may or may not be between the sills in the middle of the cars.
The Drop Bottom Gons are very interesting cars, and like so many other things on the Narrow Gauge, there are many differences from one to the next.
Mike