Q: When, (in the USA,) is a counterfeit coin not a counterfeit coin? 0

[ProfHaroldHill]

A: When it can be incuse stamped with "COPY" and then be legal to sell.

If it can be stamped COPY and be legal for sale, it was never a counterfeit to begin with, it was only an unmarked "numismatic replica", (such as are the overwhelming majority of coins referred to in this forum as "counterfeit".)

A counterfeit coin is unlawful to manufacture and cannot be made legal to possess, sell, or give away.

On the other hand, it is NOT illegal to manufacture a gorgeous, incredibly precise copy of an 1895 US Proof Morgan Dollar, (or a Seated Dollar, $20 Saint, etc,)  and NOT stamp it copy or mark it in any other fashion identifying it as being fake. You can strike a dozen, keep one and give away eleven to friends and family. No violation of law in doing that, not of the HPA, not of US Federal anti-counterfeiting law.  (Only when numismatic replicas are sold or otherwise 'placed in commerce', is there a requirement that they be clearly indicated as being copies.)

But if you strike up 100,000 precise copies, (including accurate composition,) of any of the currently in-use dollar coins, 'dutifully' stamp them all with COPY as per the HPA, and then begin selling them on ebay for $380 per thousand...

...Well, you're not going to be filling many orders before the Secret Service knocks at your door. The courts won't care that you stamped them COPY, 'in accordance with the HPA'.

It's not only better, scholastically, to be more accurate when involved in publicly discussing fakes and counterfeits, it's also important from the perspective of "legal publishment" of open accusations of counterfeiting..

Lastly, if you don't practice a fair level of precision in the public statements you make with apparent authority, the readers who matter most will assume you're probably not capable of doling so. That's just not good form.