In many cases it's very obvious, for numerous reasons, that a given coin is a proof. There are certain features or aspects which definitively mark it out as such. But with others there just doesn't seem (for me anyway) to be anything about certain coins, touted as proofs, which in any way distinguishes them from an ordinary business strike, let alone a specimen or early strike. But clearly many coins have become marked as proofs over the decades, and now sell as acknowledged proofs, often for a very high price compared to their currency contemporaries.
I look at various coins touted as proofs, and really just would not trust the descriptions/pictures enough to accept that they are. I reckon in many cases we are reliant on some individual's personal opinion from many years ago.
What is the view of others on here? Do you trust the descriptions implicitly - even the major auction house ones?
I'm using the following coin as an example of one I don't necessarily trust as being a proof. Not saying it isn't, but differences aren't hitting me in the eye. It's only an example to emphasise my point - there are many others. The coin in question is an 1859 small date penny which went for £2,400 hammer at the recent LCA. It may well be a proof, and I know Peck identified 1859 as being a date where a copper proof penny was produced. But if you can see something about it which is different to an ordinary currency strike, let me know. It's even got that little extension to the base bar of T in GRATIA, present on all the currency strikes of 1859, which might indicate it comes from the same set of dies.
link to possible 1859 proof