Is this a dust cap or an actual diaphragm in this driver?
This is the driver we are talking about.
It is an ultra low Qts driver that can be driven below Fs. They also have very high power handling. They cover the whole of the speech discrimination band. They are one of the very few midrange drivers that can achieve high spl. with a single driver.
If his dome looks OK then it is OK.
It is similar to the old Dynaudio D76 AF.
They are very similar in performance. Both very expensive. Sadly the D76 AF has not been made for many years. Also Dynaudio have not sold OEM drivers for many years unfortunately. I am currently hoarding three spares.
Billy Woodman did say he would make these mid domes available to me, if I wanted to use them in a design.
Both of those mids are among the very best mid range transducers of all time.
Those speakers sound very good in their new location.