Blued or nickel tuning pins -- Yes, it is a quandary.  I happen to like
nickel plated myself.  It looks better, it prevents rust.  It does not
get black as fast.  However, it is not historic.  If I am doing a job
for a customer or myself, I usually use nickel.  However, I also do
many historic museum restorations.  I always do these in blued steel
pins.

A museum is there to keep things as close to what was original as
possible.  Often we have to fight such idiotic ideas as, "We can't
restore that piano because then it would not be original."

If it cannot be played then what is it good for?  I think a piano in
that horrendous condition should be restored if it can be.  Let's face
it, the piano was not an item to be looked at -- it was built to be
listened to.  Museum patrons cannot imagine what an historic piano
sounded like when it last sounded good over 80 years ago.  People must
hear what an historic piano sounds like.  They often sound nothing like
a modern piano.

When we restore historic pianos we use all original substances, glues,
blued tuning pins, iron music wire where appropriate, parchment hinges,
linen dampers.  No modern supply is used in a true historic restoration.

D. L. Bullock    Piano World     St. Louis