I bought new 3 point seat belts from Amazon for a fraction of the price that the popular supply houses charge. Choice of colours was good. The only issue was that the webbing from buckle to floor attachment part was too short so I made an extension with 3/8" aircraft style cable.
This is what I bought:
https://www.carid.com/safetboy/ I see that make a "bench seat extension"; that would be easier than making one like I did!
I wouldn't mess with used stuff as it's probably pretty well worn out.
I believe the harnesses that racing guys use has a "best before" date. They are replaced before that date regardless of wear.
