King is right, when books first come out about certain guns, those interested get the research done by the author at that time. Some of this information might be incorrect, but at the time this is the only thing out there to go by.
In "L.C. Smith Shotguns" by Brophy, this was the first book that really gave the L.C. Smith student a chancce to see the differences and learn about these guns. In "The Legend Lives", Houchins basically uses the same information but with more pictures and now shows differences in guns of the same grade. However, in both books there are descrepancies in some of the writings and dates.
Most of these books are usually a collaborative effort of researchers and is so noted in the begining of the book. Very hard for one person to do this alone, so credit is due to those that write these books even though mistakes are found. Without that first printing, most of us would not know what we have and subsequent books will probably have mistakes also.