Proportioning Valve

I'm getting to the point where the brakes are gonna go together soon and while I have a stock proportioning valve, I was just pricing new ones for fun. They're ridiculously expensive so I guess that I need to know more before I spend my money.

The car is a '65 Dodge Dart with '73 Dodge Dart front brakes and suspension.

And I mean, do these pieces go bad and need to be replaced? The stock piece I have looks pretty much like this, but the goldish sort of color.

Mopar Replacement 5083808AA