There was a thread about factory floormats on Moparts Resto section a while back. Try the search function. The Mopar repro through Legendary are good. I think they say Mopar instead of Chrysler Corp or vice versa.
From what Steve Juliano showed us at a tour of his place, there were factory installed mats and then over the counter mats.
He whipped about boxed of NOS mats to show us. The over the counter's were cut to fit. So you could find a C-body mat and cut it down to fit your Barracuda.