Apparently when it's a "control test-punch", and "removed to cover the costs of the regulation labor." I also thought NGC always gave counter-stamped coins a Details grade, but this seems to be an exception. Perhaps this is common knowledge but I've not seen anything like this before. https://coins.ha.com/itm/costa-rica...odyimg-9-coin-picks-3107-CSNS-World-tem042123
What comes to mind is the Australian holey dollar and dump. I don't think I've ever seen a graded one, but my bet is they are straight graded too as they were over struck on Spanish reales, producing two coins, a donut shaped dollar and small round dump that was cut out. I'll look into it. That's a neat coin though!
That's the first holed example I've seen straight graded but it's not unusual because it was made to be that way for circulation (as opposed to someone making the hole). Some "So-Called Dollars" that were made with a hole (to be worn/placed on a ribbon) also are straight graded. As far as counterstamps, NGC does straight grade those. Here are two I found in the GC archives: https://www.greatcollections.com/Co...ais-ND-1808-Silver-960-Reis-KM-2511-NGC-VF-35 https://www.greatcollections.com/Co...amp-David-Peace-Summit-Counterstamp-NGC-MS-65
They do, when the countermark is applied by just any 3rd party. The exceptions are when the countermark/counterstamp, is applied to a coin by an official govt. issuing authority. When that is the case, and there is no other reason for a details slab, the coins get cleanly graded every time.
That's what I figured. What's interesting is that the government is giving their stamp of approval that the coin (which they didn't originally issue) meets a certain specification, which is essentially what the Chinese merchants were doing with their counterstamps.