This is true -- for original tapes.

The "error" of playing a non-Nak tape on a Nak will be preserved when you copy
the tape to an identical Nak. So it should work.

Any thoughts?

I was speaking of Nak to Nak, but I was unaware of this,
thanks for the info.

If you are comparing a Nak with a Sony, tapes made on a Nak would
only sound good on a Nak. They used a different equalization curve
than any other company. The results on a Nak to Nak were superb
but not on a different deck.