AR-4X transitional tweeter

[dynaco_dan]

Hi there;

I've downloaded a few photos of an ebay auction showing 3 - 1 /2" transistional tweeters.

These appear to be an early AR experiment of the CTS 3 - 1/2" tweeter, prior to them having a completely fiberglas covered cone.

I say early, as the pots have a black shaft and 4 bolt woofers.

Any thoughts as to why and when?

Ayone have any information about this modification?

Would the early AR-1X and AR-2X's also have used the same unit's, temporarily as well ?