Brake conversion for a 66 - proportioning valve?

[msg]

In the nineties I bought my 66 C10 and it didnt have power brakes. It was a single MC down to the drums. Many years later around 2008 I had a local custom shop do a front disc conversion for me. They bought a kit and installed it and it worked great. In 2015 I decided to do a tear down and fix up my truck and I disassembled. Recently I started buying new lines and fittings, even a new MC and was going to put it all together. I plan to run the lines from a 1/4 nickel/copper coil I bought and do the flaring myself. When I went to look for a good guide to run the lines I saw for a 1972 c10 that there is a proportioning valve in the diagram on LMC trucks site here

https://www.lmctruck.com/1967-72-che...rake-line-kits

My truck since I have owned it has never had a proportioning valve. I imagine its fine not to have it as I drove this truck for more than a decade and had no issues with braking. But if adding it in makes sense and I can get help identifying the right part to order I will plan to include it. The dual MC I just bought was a new AC Delco 18M1036 from a 1972 C10. When I look at Rockauto for the proportioning valve for 1972 C10 it doesnt show one.

Whats the right way to find the part if I should include it?

Here are some pics of the single MC when I bought it and the Dual MC after the conversion.