Chris,
There are lots of Oahu catalogue pages recently posted on the Steel Guitar Forum:
http://bb.steelguitarforum.com/viewtopic.php?t=125659
I think most (if not all) the post-war electric Oahus were made by Valco (the company that made National and Supro steels from ca. 1941 onwards) in Chicago. The "Iolana" and the "Diana" in the catalogue seem to have the "string-through" pickup used on Supros and some Nationals (the catalogue pictures have pickup covers, but the string attachment is the same as on the Supro pickups). These pickups are very "hot" - high output and great blues/overdrive sound. As for the woods used, very hard to tell from these old post-war lap steels as they were ususally covered in MOTS finish ("Mother of toilet seat").
Hope that helps!
A+ (I have to pick up some French here.
Over New Year, I learnt a new word too - "Pinard"!
)
Fred