As there is no practical need to have original floor mats in a 'classic muscle car', any old thing that fits will do. For everyday driving, use the cheapies. On 'show 'n shine' day (or just to know you have them), it's gratifying to have the proper bit of kit.

I have my reworked Whelens and now will have reworked .30-'06 and 9.3X57 brass (after I shoot them) for my 'everyday' loads. The point of properly stamped brass, for me, is one of 'coolness factor'. When I find suitable non lead hunting projectiles, I'll likely fill the 40 proper cases with them, recycle as desired.

For others, however, inaccurate headstamps could become an issue. I can't imagine confusing a 9.5X57 reformed from .30-'06 with a .30-'06 round, but I'm not so sure I'd want to use reformed brass that is headstamped for any ( )X57 that I also had a rifle for.