Mystery Bridge on old Fender P-bass. What is it?

I inherited a 70's P-bass from a friend who was a real performing NYC jazz bass player (though he didn't really like the electric bass, but I do. What the heck is it? ...). He thought it had a badass bridge, but it sure doesn't look like it to me. If anybody recognizes it, I'd love to know what it is. BTW, it plays great, though it could use a new setup. the bridge is about 3.5" wide, 2.4 " between the outside screws (and also between the E and G strings), and about 3" high, though it was routed into the bass, and the bottom is curved to match the curve of the bass. those measurements are plus or minus .05". It appears to be gold plated brass.
I've attached 3 photos.
Thanks for your help!

 

Thanks for your observations, everyone. I checked with a magnet, and it appears to be gold plated brass.I think the Alembic from the 2013 Ebay picture is the ticket - looks identical but in chrome, and with all the original pieces.

Also has a very nice routing job, and my bass came from San Francisco in the seventies, so that's another clue, as that's the home of Alembic/Stars. The only issue will be when my heirs sell it, as it's no longer a correct original Fender, but I don't mind.

Some parts may have been lost over the years. It plays well as it is, but there is no adjustment for the action, and as noted, is missing a couple of lock nuts. Anyway, thanks for your help. I think I'll pull it off and look to see if there's a stamp on the bottom. Not that it really matters, except as a matter of academic and historical interest...

 

I think you have the winning entry. Did Alembic modify Fenders, or was that likely done by a custom luthier? The routing looks identical to my bass, which also dates to the seventies in San Francisco. Anyway, thanks for your help!

 

Precisely - they may have originally done something originally, but the screws aren't origninal and the ones in there hold it down, but don't adjust the action. I'd try to figure something out, but the action is pretty good as is, so since it ain't broke... Good observation about the assortment of saddles, but I can't imagine parts are available for it, short of custom machining. Anyhow, food for thought, thanks for your input.