I do need a very good photo of front and back to help you. I need to see the quality of finishing, marks, etc. Thanks Randi
One thing you need to do is learn how a 19th and early 20th century cast iron piece feels in relationship to a later 1940s or 1960s on. Most of the time the authentic pieces are actually lighter and feel more balanced.
I paste some photos here. Let me know if you need more. I wish I could take a class somewhere just on cast iron alone. I love this stuff.
I don't expect you to see this on Thanksgiving but let me know if you saw the photos when you get a chance and if you can confirm this is a repro or suggest whether it might be authentic and worth further examination here.
To compare these two, you can see that the colorful one is heavier in weight and less distinct in detail than your example. The paint is bold, brassy and a dead giveaway. This one is easy to compare.
Here is another one. You can tell it is vintage (but still 20th century) because of its obvious where. The edges are not as cleaned as an older one would be. 3rd Quarter-late19th century cast iron forms (except for cast cooking pans) are normally lighter and more balanced than 20th century pieces. The mold residue was always meticulously cleaned on 19th century pieces. You can see pitting on this example and rust with wear on paint. But even in this condition, the paint color and some areas of this example look applied and lighter than the John Deer Color, almost as a wash was put on possibly. With my knowledge of cast iron, I would not want this one either.
this one is obviously repainted or not old, would not touch it.
Here is one that is being sold as a 1937 dealers model. Wrong paint, bad edges, wouldn't touch it, but the 2000 calendar he is showing with it has a photo of an old one on it which would be of interest for you to look at.
Look closely at the edges of your letter opener, and look at the paint with a magnifying glass. If it is old there will be at least some crazing and separations. I like the color of yours, and the cleanness of the edges, but with all of the repros around, I would still be skeptical in the future of purchasing cast items that are abundantly reproduced as it hurts the value of the real ones. If you see that the paint is really well intact but with indications of age, you should insure your example for approx. $300. My best to you, Randi