Are these speakers worth refurbing?

[walpurgis]

By the way, there were 2 variants of this tweeter - one with and one without ferro fluid. Audiomaster, along with many other box stuffers of the time, used the ferro fluid cooled variant.

Could be. I wasn't aware of that though.

I might take the front plate (+ dome) off my last pair of HD100 D25 units that I still have tucked away and see what they have in the coil gap.