Have Forum members noticed that the NEO4 description is completely silent on whether or not it plays PS2 Import Originals, let alone whether or not this is without swap.

I would conclude from this that:
the following is certain - PS2 Import Originals will not boot without a swap
the following is probable - PS2 Import Originals might require a swap
the following is possible - PS2 Import Originals cannot be played

Over to you at Playstationmods. Please clarify or make good any omission.