Holley Retrobright Price Match
So what exactly are the ramifications of using a non-DOT compliant headlight?
If you get in a crash or hit a pedestrian (etc), and your vehicle is found to have equipment that doesn't meet whatever your state's requirements are, that can go very badly for you in court, or at least with your insurance company—even if your non-spec lights (or whatever) didn't actually cause or aggravate the crash. State requirements for headlamps vary from almost nonexistent (two low beams; two or four high beams, white light, producing low and high beam) to very specific (shall meet Federal Motor Vehicle Safety Standard 108).
Honestly, I'd worry more about the ramifications (bent metal, injured or dead people) of using
bad headlamps, no matter what is or isn't marked on the lens or otherwise claimed about compliance.
if the person with the non-DOT headlights bought them under the assumption that they actually were DOT compliant (and marketed as such), wouldn't this transfer the legal burden to the seller/manufacturer of the headlight?
Not automatically, no, though if you found yourself in deep legal doo-doo, you could get them tested by a relevant lab and bring the resultant evidence of noncompliance to court in hopes of getting off easier, then go sue [in this case Holley] for fraud and file a complaint with NHTSA, the US agency in charge of vehicle safety standards, who would probably spend their usual multiple years thinking about considering whether to ponder maybe discussing some ideas about looking into it.
I would have thought Holley wouldn't be quite that stupid
They're not the only example of a formerly-reputable company turned into nothing but a brand chasing the dollars where they're easiest and giving a wink and a chuckle to applicable regulations. This is what happens when enforcement is lax, delayed, and unlikely.