Rustbucket capacitor question

[chongmagic]

C4 on the board doesn't indicate which side is positive or negative. Does this need to be a bipolar cap?

Looks like the negative end would go towards the diodes if a polarized cap was used, so negative would be the top pad?

[somnif]

It uses a non-polar symbol in the schematic , so I'd wager bipolar would be the way to go.