I have a reprint from 1974 of the Special Model parts book. It's only 44 pages, and covers special parts used on 1933-1942 Suburbans, Dubl-Duti delivery trucks, and some station wagons and ambulances. For the '41-'42 Suburbans, there are a couple pages of special parts numbers listed. These are mostly for the seats, side windows, and back door parts.
Has anyone checked with Chevs of the '40's or The Filling Station for reprints of this booklet? At one time reprints were fairly common. Maybe also try Ebay?