Compression drivers including UHF drivers does normally not need any re-charging of the magnet because Alnico V is very stable
when used with those small electrical induction levels in the HF and UHF frequencies
But those 2231A could have loosen some of the magnetic charge due to large electrical inductions from the voice coil so a re-charging of the magnet could probably be beneficially. It can be done with voice coil and cone mounted in the basket. No need for to take it out.
Btw, A hell of a restoration work for you, and it looks very very good so far