...in the description for the auction above (posted here for educational purposes, and therefore 'fair use') the seller advertises his wares thusly (underline added for emphasis):
I'm not going to sue you, so don't worry about quoting

Here you can have a sign that is made on the same old press, with the same old dies, to look exactly identical to those unaffordable items
there are differences. I am allowed to use, shall we say, marketing terms.
here is something I wrote to someone this morning about how to most quickly identify my embossed signs:
the first thing to look at is the letters "US" - they are a die pair which was made in 1989 (I've seen them in person) and the almost completely closed loop of the "S" (making it look like an "8" from a distance) is not something that was ever used on real old shields.
one of mine:
http://shields.aaroads.com/show.php?image=AZ19260702&search=70
the real thing:
http://shields.aaroads.com/show.php?image=AZ19260703&search=70
also, the mounting holes are 1/4" too low. I've never seen this elsewhere. normally, the centers of the mounting holes are 2 1/4" and 14 1/4" from the bottom tip. on mine, they are 2" and 14". you can see above the state name, they barely scrape the tops of the letters, while on the real one they do not.
so, two easy ways to check: funny letters "US", and mounting holes 1/4" too low. that's how I can tell one of mine from about 60 feet away. and if you want a foolproof guarantee, test the paint for lead. mine have no lead, of course....as the seller has repeatedly refused to mark the stamped steel signs as reproductions - and is apparently unconcerned with "protecting the investments of those who have the genuine article" when the stamped steel signs are concerned, buyers of stamped steel US Highway Shields should be wary at the very least when making such a purchase...
something else from earlier this morning:
if I etch in the word "replica" and date, someone can sandblast it right out. I'd have to etch it to 3/4 of the depth of the sign and even then someone could sandblast it and carefully metal-fill it back in. bury it for years, slap some rust on it, and no one is the wiser. so, permanent markings will not dissuade the determined counterfeiter - it just costs me time and effort. universal recognition of differences, that's the only way to go. I am open to hearing solutions. I have three criteria:
* unremovable - namely, removing it would tear up the sign sufficiently as to make a counterfeit of it nearly worthless.
* economical - I am operating on a thin profit margin; I need to be able to do this quickly and inexpensively.
* undistracting from the aesthetics of the product - so, something on the back, likely.