I have a Washburn model 5201 in for repair. There are three metal inserts on the front side of the bridge (facing the neck) - possibly brass.
Has anyone encountered this before? The bridge appears to be original, with no cracks.
I'd say not original, and most likely repair.
Probably a split bridge (check the area between the bridge pin holes) - the bridge has most likely been removed, doweled from front to back (blind hole at back) clamped up and replaced. Quite possibly to avoid having to source a replacement. I'm not entirely sure that this is a bad repair - if the thing works and the repair does its job without looking too odd I reckon it's fine.