You're reading something into my post that isn't there. Recruiting offices would be swamped.
Yup, much like 12/7/41 and 9/11/01.
As far as the original question goes, I know for a fact that assembly lines of today are far more modular than they were when tooling up for WWII. CAD programs for the toolplates and such have guaranteed us a much quicker entry into licensed assembly of government contract weapons, which we all know will happen in a world war. It wouldn't take much time for the huge corporations like the auto industry to be churning out whatever weapons were needed in comparison to the year or two it took in the 40s. I'm guessing, of course, but I also think that government contractors already know which corporations employ the types of assembly best suited for a quick turnover to their products.