Also in the auction is a Phar Lap photograph album from the Davis family.
It includes 36 black and white photographs of the finishes of all of Phar Lap's race wins in Australia.
It is the only known complete set of photographs of the horse's Australian wins.
The album is estimated to be worth between $100,000 and $130,000.
The two items will go under the hammer at the Leonard Joel horse racing and other sporting memorabilia auction about midday tomorrow (Sunday).
Phar Lap was foaled in New Zealand but trained and raced in Australia. He won the Melbourne Cup in 1930, one of 36 wins in Australia before he died unexpectedly in America 1932.
His skeleton is displayed at Wellington's Te Papa, but his hide is displayed at the Melbourne Museum and his heart at the National Museum of Australia in Canberra.
This year's Melbourne Cup is on Tuesday.