A few years ago the short lived Brisbane 'Celtic Club' ran whistle classes. Some of the players drilled their own back hole exactly the same as on this whistle, on a standard D Generation.

...

The Celtic Club guys - if they got the placing right after the first few tries, placed it dead between the top 2 holes.

So, NOT exactly the same. That "Celtic Club" configuration is what Turkish whistles have (same layout as on the mey, duduk or kaval).
Gives you a C natural, sort of.