Another vote for covered from me.
Nickel if your bridge and saddles are nickel, but chrome if they are chrome. (sorry if that sounds obvious).
I got nickel covers on mine, as the Gibson site said the fittings on mine were nickel.
WRONG !
I was therefore to discover that the rest of the guitar's hardware was in fact chrome. The slight yellow/blue clash of nickel/chrome hues looks a bit 'out' but is not the end of the world.
I cannot comment on unpotted though, for whilst I wish I had have ordered mine un-potted, I too was unsure of the possibility of 'pickup 'squeal' at the time so went ahead with potted.
Regards,
Derek.