Saginaw PS pump pressure valve

[Cadillac Kid]

Hello everyone.

Ive got all of the accessories off of the front of my 350. The power steering pump is shot, so I'm planning on keeping the original housing and putting new pump in it to save costs. Is it recommended to replace the power steering pressure relief valve at the same time? I have had a hard time trying to find a new one for sale. I don't think there quite replacement parts. Someone told me that if your rebuilding the pump, I need to change the valve as well. The old pump was notchy and groaned very loud when I had the motor running.
What is the protocol for these old saginaw pumps.

Thanks

-Gavin