Hi,
I have reconditioned several of these speakers.
Yes, they can be repainted. Though I usually don't repaint the front cause you will loose the lettering, but the sides, top and bottom are easily repainted after light sanding and filling. The speakers have a little glossy line running horizontally in the middle, which you either have to mask off or put back on later with glossy paint.
As they are cast alu, I did finish a pair in high gloss polished chromeplating..... spectacular......I also have done a pair in a super sparkly lipstick red carpaint finish (done by pro!)... very nice too....
These kind of speakers are usually fairly easy to find and not too expensive ( I ususally pay max $100 a pair) so I find it ok too mess with them al little and it doesn't rely take away any of the value.
Regards