I am highly confident it is authentic. Czechoslovakian seltzer bottles are quite often used by US companies...they made many of them. I have a large New Hampshire seltzer bottle collection and several of them are Czech. The etching is done right...some of the reproductions I see are sandblasted rather than acid etched, but this one is good. I've seen the exact same logo on different styles of seltzer bottles before; I think the bottles were imported in bulk blank and then the etching and marking of the metal parts were done here in the US. The fact that the logo is the same as the one on another seltzer you have would actually give me more confidence that it is authentic, as the stencil for this logo obviously is unlikely to still exist. Also, the seller is in Kentucky, so that is a very good sign.
As you noted, the seltzers that have been "reproduced" are large-brand seltzers and most of those are actually fantasy pieces done on South American seltzer bottles.
My main concern with this bottle is the price. I think the seller is crazy to ask so much for it. The market for these standard US seltzer bottles is pretty small and even nice bottles typically do not pull more than about $50...$100 on a very good day with two people that really want one. This one is lacking the correct top as well (which is common but brings down the value).
As you noted, the seltzers that have been "reproduced" are large-brand seltzers and most of those are actually fantasy pieces done on South American seltzer bottles.
My main concern with this bottle is the price. I think the seller is crazy to ask so much for it. The market for these standard US seltzer bottles is pretty small and even nice bottles typically do not pull more than about $50...$100 on a very good day with two people that really want one. This one is lacking the correct top as well (which is common but brings down the value).