Sterling by MusicMan Bass? Unsure of origin of this one.

Proud owner of a Sterling by Music Man Bass today as I got it from Facebook MarketPlace. However I’m unsure what I have here. Logo is the Ernie Ball Music Man Sterling kind but I have a Sterling by Music man plate. This bass looks dusty as all heck and seems original at least from my eyes. Could this be some sort of Frankenbass or a really old start to the Sterling import line. Including photos below.