If the foam surrounds have rotted and are falling apart, they can be repaired.
If one shows rot, the other three will also be bad or at least marginal.
If a woofer is no longer playing, it will most likely need replacing.
The woofers are 6 ohms and will be hard to match with modern types.
I have a set of original woofers, refoam'ed and ready.
No midranges though.
Martin