Valoy II - a strange focusing ring

Hello! I have been a fan of the Leitz Valoy II enlarger for a long time and I recently found a later grey version which came with an unusual (to me) focus ring. Or perhaps you'd call that the helical? It is the large round holder for the lens. Over twenty Valoy II's must have passed through my hands, but I have never seen this focusing ring.

Normally we use a separate extension ring in between the lens and this focusing ring. It is called DOORX or 17675 and it lowers the lens by 15mm. The Focomat Ic has these rings and they're essential for the automatic focus. The Valoy II is more simple, it does not have automatic focus. But the extension ring is still important as it makes the lens more accessible.

The focusing ring I just found has a different design from the original:

- it has the same diameter, but it is not as long as the original

- inside there's a M39 threaded ring attached with 3 black screws, it has the same function as the DOORX extension ring.

- the knurled ring at the bottom is wider

The attached images should explain better than my poor English. What it comes down to is both focusing rings do the same, even though the interior designs are very different. When I put them next to each other with the DOORX ring and a Focotar they line up at the bottom and the top . . .

Has anyone ever seen this unusual ring, or does anyone know anything about it? Also it is possible you have it in your Valoy II without knowing. I wonder if it was made by Leitz. I looks like it in a more modern sense. Perhaps near the end of the production? The improvements would be 1) no more separate extension rings, 2) easier access to the lens and 3) the wider knurled ring . . .

Thanks, Michael

pictures attached. In the last picture the old original focusing ring looks smaller, but it isn't. It moved to the back . . .