Meade 4000 Super Plossl "Japan" 4 or 5 element

Does anyone know if all Meade Series 4000 Super Plossl eyepieces, "Japan" made versions, are 5 element type?
There is the "Japan" made version -Smooth-Side- which I'm sure is a 5 element type, but is the newer "Japan" made version with rubber eye cup on top a 4 or 5 element type?
Does the 4 or 5 element type perform better?
BTW: I'm looking for a 6.4mm "Japan" EP.

I browsed through my collection of Astronomy magazines.
The May 1993 Meade ad still lists the Series 4000 eyepieces as having 5 elements. The September 1994 ad describes the Series
4000 as having 4 elements, "updated and redesigned to utilize
the lastest in optical glass types for 1994".

I've heard that the 5-element ones were actually made by
Masuyama in Japan. I can't comment on which type performs
better.

The 4000 smoothies with Japan mark are a 5-element design -- not a Plossl at all from what I understand but actually a pseudo-Masuyama design. I have all of them except for the 15mm which seems to be quite extinct from the used market as I have been searching for one for the better part of a year.

I've always seen the 4000's with the rubber grips advertised as 4-element Plossls. I have used the 4000 Japan 4-element Plossls and they are no where near as good performing as the 5-element smoothies.

Of the smoothies, I find the 26mm to be to dog of the line being very poor performing off-axis. The 20mm I'd rate good. The 40, 32, 12.x, 9.x, and 6.x are simply outstanding and easily hold their own with any other Plossl out there IMO.

For a very brief time, the five element (Masuyama design) were made with the rubberized barrels similar to the later four elements designs.

The way to tell if you have one of these (other than optically counting the reflections) is that the word "Japan" was stamped at the bottom edge of the black barrel. The later four element models that were made in Japan had that stamped on the lower, chrome barrel.

Dave