WM parts-body and MC

["Joseph M. Shaw, II" <MikeIIDC@domain.elided>]

Help, Please!

I have three weeks off from school for Christmas starting in two weeks.
I want to completely bring the WM up to par during this time.  I've had
some input on my Master Cylinder problems, but want to pose this
question once more before ordering parts.
If my MC is leaking out the back, where it joins the brake booster
"drum," does this mean I need a new MC, new gasket of some kind only, or
something else?  Brakes seem to work fine, though I haven't driven it
much more than a block at a time yet.  It doesn't leak enough to notice,
even though I always check it.  The only way I discovered it is through
the amount of smoke that comes off the exhaust once the engine is warm. 
It only comes off that side, and finally I noticed the pattern of
wetness on the booster, etc.  So, what do you experts think?
Also, I earlier asked about body parts for the WagonMaster.  Several
people wrote that they were the same as the T'all, which I realize, but
in getting the rear "quarters" are they made differently than the T'all
because they are cut off at window level?  I don't want to buy T'all
parts or a parts truck, and find that to get them cut down to match
leaves something to be desired.  Did IH make special quarters for this
limited purpose?  These are the only parts on this truck that really
show any rust and I would like to replace them.  They have the rust
above the rear wheels, and a few dents.
Any input among those of you more knowledgeable than me that these are
the EXACT same parts?

Thanks!

Michael