Robert,
Looking at more pictures tonight, I would say you would be safe using the the same siding on models of the reefers and boxcars. As we know, over time cars received new siding and things changed. You would just have to compare pictures of the cars you are interested in modeling.
As far as what The Leadville Shops did on their models, you'll have to ask them. Replicating the bead board feature is tough. In O scale, the 1/4" wide bead would only be .005" wide.
Here are some UP/Tiffany reefers showing the bead board.
Doug
Doug Heitkamp
Centennial, CO