I read years ago about the problems with finishes lifting on rosewood.
I would think rosewood _veneer_ has similar problems.  The finer guitar
builders use only lacquer after cleaning the rosewood with several
washings of lacquer thinner.  Any type of polyurethane finish is a
no-no with antique instruments.

Shellac would be my first choice on an antique piano as that
would more closely resemble the original finish.  It also makes an
excellent base coat for any other finish.

We cringe when a piano comes into the shop with a poly finish.

Don Teach
Shreveport, Louisiana