It has long been a moot point. As a rule of thumb, I think you need to view proofs as things that are better than specimens and struck from highly polished dies. In the case of the 1937 sets, it may just be that they used the word specimen as in 'an example of' because this is the only year (I think) that this phrase is used. The 1935 crowns were issued in presentation cases alongside a general issue from the banks. The mintage of over 700,000 tells us that most can't have been boxed, otherwise we would be surrounded by empty boxes. Those in the boxes were presumably produced as a specific run using a fresh die pair, but are inferior to genuine proofs. If you look at the Victorian era cons, you have the same arguments trotted out where the Heaton mint bronzes from the 1870s have long been contentious. It is not questioned that they are a superior product, but when compared against a known proof they fall slightly short resulting in some such as Freeman calling them proofs while others condemn them as not being so. Somewhere on here is an image of a currency, common year proof and VIP proof shilling alongside each other for comparison. If someone can find it please linkify, o/w I'll have to repost it. Ta.