Answer: it all depends on how many you build.
Every factory is different depending on output, projected life, land costs, worker availability, market, etc. The Proton factory takes in sheet material at one end and outputs cars at the other though their engines,transmissions and interiors and built at nearby factories. The biggest factory building I have seen is Boeing, but the combined components factories areas to support a high production rate auto manufacturer would dwarf that, causing an inefficiency. Fully integrated factories are limited in their output to very low production numbers. Most american factories assemble components made here and abroad and make nothing on site though their sites are huge.
Smaller manufacturers like Roush still order raw material and build all frame and chassis components on site and spec seats, brakes, axles and other bolt on components from other manufacturers. This requires up front money to clear a work center, like one of their main street buildings, order and stock the raw material, set up the work areas and equipment, and hire or reassign workers to the tasks. The first ton of Aluminum structural shapes and sheet can be delivered typically within a month of ordering ( very available) with a 60 day net, but the carbon fiber may require two week payment due to high demand ( luckily Boeing related usage has caused more manufacturing centers to be built which has increased supply). The bolt on stuff will most likely be 30 day net. Roush would not order anything without cash up front especially when they have the cash drain of two NASCAR racers with no corporate sponsors. I havent heard of any shift in their various shop buildings as yet nor seen any announcement from them similar to when they built a dozen GT40's (under license from Safir).
A new manufacturer would be asked to pay upfront for any delivery, and in many cases cash in advance.