I purchased the King Pin set from the fillingstation and it came with what I'm assuming is a new thrust bearing, but it's a solid thick washer. My old roller thrust bearing is shot, so do I replace it with the new thick steel washer and a single dust cap?

If anyone has run into this, please let me know what I need to do for a replacement thrust washer. Also, what is the bronze colored washer for?
Thanks!
Filling station king pin set