Bruce,

I've worked on an accumulated like this somewhere, just do not remember
what instrument.  In any case, I believe that you have everything that
is needed to make this accumulator work.  Yes there are some unfilled
bolt holes, but they may have been for another designed, ie; electric
operation.  If you are not familiar with its operation, I'll explain.

When you drop a coin in, the coin will flip the small lever on the right
side.  This will cause the accumulator wheel (in the center) to be pulled
one click clockwise.  This in turn will allow the small lever on the left
to lift and the knife switch to close, completing the electrical circuit.
 When an "OFF" signal is sensed from the roll, that small pneumatic in
the upper left corner will activate, pulling the accumulator wheel one
click anti-clockwise.  This will in turn lift the lever and open the
electrical circuit.

For this to work, everything must move freely - ie:  no grease or dirt.
There is a spring on the underside of the accumulator wheel.  This must
be adjust correctly, with a little tension on it when in the "0" position.
 Chances are that it is completely unwound (or missing).  If so, the wheel
will never increment when a coin is put in, as this is what moves  the
wheel clockwise when the coin is dropped.  Please write if you have any
questions.

Sincerely, 
Jim Quashnock