Agreeds. One of the most obvious differences is the bottom of the bottle. Some are flat and some are concave.
I didn't even suggest that and, although there might be some exceptions. Do wineries manufacture their own bottles?
If many (if not most) wineries buy bottles wholesale from a manufacturer, I imagine many wineries would use the same bottles for wines that might vary greatly in quality and price.
And, as I indicated in my previous post, that "problem"might be avoided if the counterfeiter buys a cheaper vintage of the same wine (Malbec, e.g.) from the same winery and changes the label to a more expensive vintage.
If they try that, however, people who often buy the same wine over and over are (IMO) more likely to recognize a difference in the taste of the wine itself.
PS: I just checked to see if there was any difference in wine bottles from three different wineries and, except for the labels, they were all exactly the same, but I also realize there are a number of styles of bottles that are used (even) by the same winery. It's something the counterfeiters would have to be aware of and be careful to avoid making an obvious mistake.