Pin Lock Keg Pressure Release Valve O-Ring Replacement

What is the O-Ring size for the Pressure Relief Valve on a Firestone Pin Lock Keg lid? I would just feel better replacing those $0.15 o-rings now, the valves all look fine.

I have been trying to search for the answer to my question but have not been able to find the answer.

I picked up some Firestone Pin Lock Kegs, I have cleaned them and thought I had all the O-rings that I needed. I then decided to take apart the lids. I found 1 more o-ring on the lid that nobody mentions the O-Ring size for.
Yes I know for around $10.00 I can replace the PRV with new ones or I could buy new lids with the Pepsi style PRV for around $16.00 or so.

This O-Ring size

I found the size O-Ring Needed it is a 9/16 x 11/16 x 1/16. Sizes
dash -015
BrassCraft 0581

I have 2 kegs under pressure with these replacement O-Rings. I just wanted to replace all 6 O-Rings not just the 5 you get in the kits. So my kegs are cleaned, rebuilt and if pressure holds. I will be adding cider and Apricot Blonde tomorrow.