Hi Randall and list.  Sounds like you are having fun.

Motor leads:  I would remove the tape very carefully, then put new wire
to the fuse box and retape.  I would not replace the leads to the
motor.  They should be okay.

The oil reservoirs: they do not have seals.  I would remove the oil
level fittings and try to clean the reservoirs out as much as possible
with solvent.  Then put in new oil.  Years of oiling, some carelessly,
plus the fact oil creeps, makes a mess if it's not cleaned up
regularly.

The L and R is an adjustment for rotation: R for right rotation and
L for left rotation.  There are marker lines at the correct location
for that direction.

The damper drives were more effective on single-phase motors than
3-phase motors, like the 7-1/2 HP single-phase motor I have which is
most likely bigger and heavier than your 10-HP 3-phase motor.  I think
it weighs more than 400 pounds, by the way the chain hoist was acting.
It is larger than a 30 HP 3-phase motor that I have.

It was said that when the organ was turned on everyone in the small
town knew it because all the lights would dim.

Russell Doering

 [ The single-phase repulsion-induction motor, even though it's quite
 [ expensive, is favored because the starting current is only slightly
 [ more than the run (operating) current.  It won't overheat if it
 [ takes 10 to 30 seconds to accelerate to running speed.  An induction
 [ motor (single-phase or multi-phase) which spins a massive inertial
 [ load, like a grinder wheel or turbine blower, demands many times the
 [ run current while starting, and so a heavy-duty mains supply must be
 [ provided (and that often costs more than the motor!).  -- Robbie