Worth a comparison

[PeteM]

In this case I don't think so since this lens was used as part of the MPE system . . .

You're probably right. However, the photo of the lens (posted by Nikon User when he said it simply unscrews) doesn't look like the one you tried (or mine, somewhat different, but from an MPS system).

[Scarodactyl]

Yeah, his is clearly different even if it's somewhat echoed in the good resolution of the one I tested.