How can I tell if the wine I won at auction is legitmate?

Hello there! I'm Dr. Vinifera, but you can call me Vinny. Ask me your toughest wine questions, from the fine points of etiquette to the science of winemaking. And don't worry, I'm no wine snob—you can also ask me those "dumb questions" you're too embarrased to ask your wine geek friends! I hope you find my answers educational, empowering and even amusing. And don't forget to check out my most asked questions and my full archives for all my Q&A classics.
Dear Dr. Vinny,
I won a wine at auction, a 1979 Opus One magnum. When I received it, the condition of the capsule and wine label were surprisingly good. However, the back label looks different from the other recent Opus Ones. I also don’t understand the number and symbols on the bottom of the bottle. Should I trust the seller?
—Andre L., Berkeley, Calif.
Dear Andre,
I showed the photos you provided with your email to the fine folks at Opus One, and they said your bottle looks just like the magnums of ’79 they have in their own cellar. Sometimes the labels of larger-format bottles look a little different than those on standard-size bottles, and even the most classic labels have been tweaked over the years.
The embossing on the bottle itself is what’s called a “maker’s mark,” indicating which glass company made the bottle. Typically these marks are on the bottom rim of a wine bottle or hidden inside the punt (the cone-shaped indentation in the bottom of most bottles), where it doesn’t interfere with the rest of the packaging.
Go ahead, grab that bottle of wine and look for the maker’s mark. Sometimes you can’t even see it, but if you run your finger over the bottom edge of the bottle or inside the punt, you’ll find it. That’s another piece of information you can check if you’re concerned about the authenticity of a bottle.
—Dr. Vinny