I wouldn't be surprised if the bass originally left the factory with a standard white pickguard on it. Someone probably didn't like the look of it and changed it to the black pearloid that was on it.
You can always ask the customer service people (by giving them the serial number of the bass) what the configuration of the bass was when it left the factory. They'll tell you for sure.
There's no doubt about it, your SR5 looks great with this color combination.