If the keys of a restored piano are spaced unevenly, I would question
the quality of the restoration. I have seen many such "restorations."
1) If the front rail bushings are worn, moth-eaten or have fallen
out, the keys can move side to side and give a very uneven appearance.
There needs to be a little side play, about 1/64 inch, in order for
the keys not to bind.
2) If the front rail bushings are tight and the keys are still unevenly
spaced, this is corrected by spacing the keys. This involves use of a
key spacing tool on the front rail pins, bending the pins to the left
Since front rail pins have flattened sides in their working area
(appear oval from above) sometimes a quick fix for loose bushings can
be effected by using the spacing tool to turn the pins enough to take
up the slack. This is not a long lasting repair, as wear is
accelerated by reducing the contact area with the pin.