On ‘American Restorations’ the restoration process often includes adding original artwork (likely copyrighted) and/or trademarks (including some that are still in use, like Coca-Cola and Pepsi).
Could they be liable for infringement? (If so, I assume there’s some off-camera work to get necessary permissions). I’d love to hear from any professional restorers or copyright/trademark reps (that have been in charge of granting/denying permission).
Copyright is the right to make copies.
I’m quite sure that restoring an antique sign or Coke machine would not really fall under the copyright law at all. One would be reapplying or restoring a trademark created to advertise the copyright holder’s own product.
Producing multiple “antique reproductions” of something still protected by copyright could be a problem.
The decision isn’t one off vs mass produced.
The main point is if it hurts the artist or the owner of the art.
Of course mass producing someone elses art hurts them, but the point is that a one off can hurt the artist or the owner of the art…
Hanging a copy of Mona Lisa in a large neo-classic looking art gallery , with the name “Louver”, in Paris ? Just paint up some old school building and stick a glass pyramid in front of it… Perhaps copyright might apply… damaging the owner of the original, right ?
When a vending machine is repainted as a Pepsi machine… it doesn’t hurt Pepsi, and it has merit in preserving history.
But they might get into trouble if they produced picture of Elvis Presley ? Well perhaps…Elvis wasn’t mass produced so therefore its easier to see how it hurts the copyright owner ?
WAG: Repairing something is legally not the same as fraudulently using the trademark to sell a different product.
I don’t think for a second that the trademark/copyright owners would be opposed to it, or even care, I’m more curious about the purely legal aspect.
A trademark implies that a product has been certified* to the mark-holders quality standards. With a restoration, replica, or reproduction, this is no longer true. The mark holder has no assurance that it meets the same quality standards they set for the original.
*either individually or of the overall production process (i.e. “follow these steps and we’ll get the quality level we want”)
Legally, the trademark only indicates the origin of the goods to a prospective customer. It doesn’t imply that the product has passed any safety or purity standards.
Restoring a trademark doesn’t alter the origin of the goods, nor is it intended to mislead consumers. This makes it extremely unlikely that the trademark’s owner would sue the antique restorer for appropriation or misuse of their trademark.
De minimis non curat lex.
“The law does not concern itself with trifles”, for those of you who didn’t study Law or Latin. 
It’s also the legal doctrine behind why you can’t have people charged with assault for accidentally bumping into you when you’re walking down the street, for example.
If you have a Coke machine that was legally produced with Coke’s permission to use the trademark logo, that permission never goes away. The machine has permission to display the logo and that’s the end of it. Whether that logo is beat up or freshly repainted is irrelevant.
If you take some random machine and take it upon yourself to put Coke logos on it, then you’re violating trademark.
the restoration process often includes adding original artwork (likely copyrighted)
I’ve seen the show many times and mostly what they do is recreate the original artwork. It isn’t a violation of copyright because they’re just putting something back where it was originally. However, if they decided to copy that artwork onto something else, without the permission of the copyright holder, then that would be a violation.