I think devs have much more real material for make the maps, here is when I miss some kind of "dev blog" or "dev" explanations about the historical background of the maps.
Actualy they where inside the grain elevator ..imo as some of the first "westebers" since ww2. Dont know where the thread went but there where rater excessive reports about that trip around these very forums dateing back to early 2010 or late 2009 i think. Maybeh a mod can dig them out..it was a highly intresting read.