Well, I'm not an attorney, don't even play one on the radio, but back in
my museum curator days we were taught that the recipient (then, the
museum we worked for) could not establish value, as we were considered 
"an interested party" by the IRS.  Value was to be set by the donor, 
usually by getting an appraisal.  One way to do this, I would think, 
is to have the price on sales of a similar instrument to compare to, 
at least three, I would think.  Most "antique appraisers" really don't
have an understanding of mechanical music instruments, so you should ask
around before hiring one.

David Dewey