Hi Paranoid.
I haven't seen any *proof* one way or the other. Yes, they're built in the mid-west (Indiana), but remember, they're also built at a Toyota plant, which normally means at least a smidgen of better quality.
I'd rest assured that your truck will be just fine, regardless of what day of the week it is built. Besides, with a build date, isn't that just the finish date? It was probably built the day before, and then finished on Friday (right before knocking off for a few brews!)
EDJ