Ok here's an update. I found another one on ebay from the same place, only this time... the etching is more closely reflecting an original example. This is going to be a lengthy post. Let's start with a composite of a bunch of genuine FBU examples collected from my own holdings as well as all over ebay and the internet, so we can get an idea of how much the fonts and positionings varied (hint: not actually that much). I'm going to analyze all of these and figured a good sample size would be nice to make claims.
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And looking closer, we can see some characteristics of the original acid-etched examples, most notably non-uniform fonts and rough text edges due to the etching process:
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Below, left, is the first re-etched example I saw on ebay. You can see it's very, very poorly done. The middle image is the most recent one I found, which is better and obviously after learning some things to make it look more original. To someone who knows fonts well, the 'FOR BARBER'S USE' part especially should look glaring in comparison. A genuine example is at the right.
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Here is an in-depth comparison. Some things to assist in comparison: 1. The height of the cross of the 't' is different in the most recent re-etch than in all other vintage samples (red). 2. The general shape and ratios of the letters is different (blue). 3. The small blackletter 'e's are missing a part at the lower left that is seen in all old examples (orange). 4. The length of mid-level horizontal lines of 'F' and 'E' relative to top and bottom is incorrect (purple). 5. Original fonts had very rounded, prominent serifs (green). These are sharper and smaller on the re-etched example.
There are other small details but this is a good sampling to get you to recognize how to spot these.
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Finally, on this particular example, there is clear evidence of buffing on the tang, with a very fresh looking grind on the blade face. This has been reground, however it clearly has a nice crisp etch. Compare another example with original etch that has been reground and polished:
Attachment 240703
The latest one I came across was listed as 'restored' and not 're-etched'.