it's quite normal for basses to have different saddle lengths as they were probably adjusted during set-up at the shop / factory. if anything feels wrong about the bass or intonation is bad, i would recommend a trip down to a guitar tech.
It's at the bridge, the one with the springs. It's usually not set to equal length cause different bass have different intonation, I guess. That's why it's set as such to suit different intonation.