Kyocera and Solen caps question

Wonder if anyone has come across this before, I just got one of these caps:
and it came with a dot marked by one of the terminals. Does anyone know if that indicates a preferential polarity, an outside foil or whatever? There is nothing written anywhere about it.
I noticed larger capacity Solen PP have a + indicator as well. Should that be taken as the preferential plus or high impedance side connection?