"Fixed" dates

Quite a lot of banknotes have a date on them that has very little if anything to do with when they were actually issued. Examples include many notes with the date of the legislation by which they were authorized. We're not very consistent about how we record these, partly because it isn't always obvious that a date is "fixed" and not "real". In some cases, when we know the given date is not applicable, we list notes as ND and give the actual date(s) of issue separately.
I wonder if there's scope to have another option of "Fixed date"? This could also apply to some coins (I'm thinking particularly of many Indian pieces). This would give us a more consistent way of displaying what can be a rather confusing situation. Of course, we'll have to decide what constitutes a fixed date (i.e., how many years must have passed) but I wonder if the added flexibility would be advantageous?

I agree. One extreme example for a coin is the Maria Theresia Thaler.

Would the U.S. Bicentennial coins (dated 1976 but minted in 1975 and 1976) be considered "fixed year" coins?

By the guidelines they should be ND (1975-1976) but they are currently listed as 1976.
https://en.numista.com/catalogue/pieces56.html
https://en.numista.com/catalogue/pieces1489.html
https://en.numista.com/catalogue/pieces3366.html

I believe that a very large number of coins were minted at least in part in the year before release I think if it is not that much more we should be lenient.

Απόσπασμα: "bjherbison"​Would the U.S. Bicentennial coins (dated 1976 but minted in 1975 and 1976) be considered "fixed year" coins?
​
​By the guidelines they should be ND (1975-1976) but they are currently listed as 1976.
​https://en.numista.com/catalogue/pieces56.html
​https://en.numista.com/catalogue/pieces1489.html
​https://en.numista.com/catalogue/pieces3366.html

​This is a good example of the ambiguity we face. I agree with Idolenz that leniency here would be appropriate but the question is, how lenient should we be? Is 2 years too much? I think we can all agree on pieces like the Maria Theresia Thaler but this notion will get discredited if we're too eager.