in RS178, the initial consist (1929) was described as including "three (sic) sixteen section sleeping cars". all other places that consist is listed, however, only states there were 2 tourist sleepers. this is the only place i've seen the sleeper type qualified as a number of sections.
but from: http://www.northeast.railfan.net/classic/CARdwgs4.html
it says 16-section Pullman production ended by 1918, so those cars were almost 20 years old by the time the EB started to run, thus maybe only ran for the first few years if that.
my guess is that the tourist sleepers were Pullman pool cars, and i'm even doubting they were lettered EMPIRE BUILDER but rather, maybe, PULLMAN.
but you're right. you'd think that RS110 would at least mention the 16 section type if they were ever in a GN consist.
i may try to follow-up with a question to the society. i picked up a few other Ref Sheets and discovered it was cheaper to join and get the society discount. may as well use the annual membership!