Gibson used plastic bridges from 63-64, it was a terrible idea and they were history by '65.
You say yours is "showing signs of age" - if it's not broke, don't fix it, as they say. If and when it gives out, have a respectable luthier replace it with a fixed rosewood bridge, don't replace a sh***y bridge with another sh***y bridge.
Here's what the underside of your plastic bridge looks like, with all its hardware. You really don't want to replicate all this mess, do you?