John , your photo is quite interesting .

Clearly from all the great information presented in this thread so far, the usage of the 23746 ( oem stamp ) wasn't limited to only one back-cap style neither was it used exclusively with the two phase plug types ( which negates claims for it being either a 806-8A or 806-8B / my bad ! sorry ! ) .

Therefore , I need to ask; what was the actual determining factor ( commonality ) for inking that 23746 stamp onto a driver ?
- ( So far it looks like any 806-8x body type loaded with a 23744 diaphragm covered with any back-cap style, was all that was required )

<> cheers