Proportioning valves: abs v non-abs

[87MJTIM]

Moving forward with a booster upgrade and swapping to an XJ prop valve. The one I got with the booster only has 4 ports: 2 in and 2 out. The port in the back is plugged. 
 

Normally, the valve should have 5 ports: 2 in, 1 for RF, 1 for LF, and 1 for the rear. 
 

Since the abs controls each wheel it stands to reason it only needs 2 inputs: 1 front, 1 rear. 
 

Am I correct? Do I have the wrong valve?

 

EDIT:

 

I may have found my answer.

 

https://www.jeepforum.com/threads/proportioning-valve.787040/

[Eagle]

Do you still have the rear height-sensing proportioning valve in your truck? If so, you need two lines to the rear. Even pre-ABS, the MJ front distribution block was different from the XJ proportioning valve.

 

 

 

[87MJTIM]

The LSV was deleted years ago. 
 

I picked up two prop valves at the JY yesterday. One from an XJ with rear drums. The other was from a ZJ with disc ABS - only one line for front brakes. I watch a YouTube video on converting this to handle non-ABS. 
 

I will run one new line to the rear eliminating both old lines.