With Patek Philippe Extract from the Archives confirming production of the present watch in 1939 and its subsequent sale on February 5th of the following year.
Reference 524, along with Reference 523, was produced from 1936 through 1940, and is one of the very few asymmetrical shape watches made by Patek Philippe. They were also used as driver's watches, because the shape allowed for better readability of the dial when on the wrist, holding the steering wheel.
References 523 and 524 were made with two calibers - the small round cal. 8"85 and more rare tonneau-shape cal. 9'''90. The main difference between the two references is the case back. Only a few hundred pieces of the two references were made overall.
For an example of a reference 523, please see Lot 155 in this sale.