the repair kit is universal, covers 1935-56. The black gaskets might be for the earlier trucks or as Tim suggested a rear cover.
the manual shows 2 steel washers
...link... Fig 76... I dont thik the washers are reproduced. if your missing one try posting an ad in the parts wanted section of the forum, or have a machinist make one for you.
I was lucky enough to have a fellow stovebolter help me out with washers and advise when I replaced my ball seals last year.
