It is fine electrically, but expect the higher voltage units to be bigger, probably both broader and taller than the ones you took out. If you can make them fit then great, but try not to leave too much lead length or wire them back to the PCB with wires (extra inductance, not good on SMPS).
The side with the stripe is "-", just be sure the new ones are orientated as the old ones were, the photos here could serve as reference, also i'd guess the shading and black lines on the PCB indicate the "-" side.