The handmade automobile commissioned by the maharajah, also known as Sahib Bahudur Singh, is powered by an 8 litre, 6-cylinder engine with dual spark ignition set to a low gearing ratio that allowed it to creep powerfully through the jungles of Rajasthan.
Umed Singh II who ruled Kota in Rajasthan from 1889 to 1940 is said to have been an avid hunter.
The Rolls-Royce company employed London coach builders Barker & Company to craft the specialised touring body for the royal and then shipped it to Mumbai.
In addition to standard luxury fittings the motorcar contains a hidden safe, a nickel-plated hissing snake horn, mounted Howdah gun (double-barrel shotgun in pistol form), rifle stand in the rear passenger compartment.
The Phantom also featured a mountable Lantaka cannon, attached to the bumper and a machine gun mounted on an attached matching trailer.
Collectors in UK and US previously owned the marque Tourer, that has undergone two restorations in the 1960s and 1980s, says the auction house.
It is said that India accounted for over one third of the Rolls Royce sales between the two world wars. Erstwhile Indian royals from Patiala, Bharatpur, Alwar, Mysore, Travancore were among those who purchased the automobiles.
Bonhams conducts the Quail Lodge sale every year in August in Carmel, California during the famed Pebble Beach Car Week.