Things are not always what they seem. It's an illusion, due to the angle, lighting, what have you. Id put large sums of money on it.
I'll leave you with this.
Browse pictures of him with his various Jazz basses, including this one.
Are there any other pictures that make you think the bridge on this or the others, is anything but a standard bent plate Fender bridge?
I think you will find the answer is no.
So with that in mind - why would this be different? Is it possible he tried another bridge on this instrument,and later reverted back to the stock bridge? Sure, anything is.
But......
Is it likely, considering every other picture of this bass AND his other basses show the stock bridge?
I think not.
Just a lighting effect. It's not a very high resolution photo either.