Eric Shoemaker's request for components to replace those missing from
a Steinway model OR brought back many memories.  First the good news.
Steinway stacks for models XR and OR are the same, thus making the
search somewhat easier, as OR models are scarce, but XR models are not.

However, the correct vintage of the gutted piano must be identified so
the style of the stack can be correct.  Early Steinways have larger
stacks with the pneumatics aft of the striker poppets, while 1925 and
later models have the pneumatics forward of the striker poppets.  To
further complicate matters, the lever styles also come in two types.
The earlier type has the "Tempo-manic" control, while _most_ later
models do not.  There are exceptions.  Most OR models are the earlier
and larger stack, with Tempo-manic controls.

The next variable is the spool box.  Two styles are closely associated
with the two styles of stacks, but exceptions do occur.  Earlier spool
boxes mount on the key frame.  Later styles are suspended above the key
frame and are mounted on the board in front of the pin block.  Air
motors also follow that same scheme with a hybrid exception where the
spool box is mounted on the key frame but the air motor suspended
above.  Air motors suspended above occupy a space under the pin block
and the pin block will have been notched out to provide clearance.

Retrofitting a Duo-Art is an huge task.  The levers are a nightmare.
My guess is the piano in question had the large stack, key frame
mounted spool box and air motor, and the levers were the Tempo-namic
style.  All of this can be verified through close examination of the
piano.  The real horror story is the Tempo-namic compound linkage, part
of which was mounted on the expression box, and since that is gone
too -- well, you see what I mean.

In case you need new style key slip brass levers, I have some.
Good luck!

Bob Taylor