I missed one that might help, This is a 4 roller machine

Yes, I recall you saying it was four roller but that doesn't mean it couldn't show up with 5 roller mountings:)
Can't quite see the bolting, is it four bolts on that inside bracket??
I'll get a picture for comparison and post tomorrow.

I'm glad to be of some help, but I've got to confess that I found out a bit more about the track adjuster(s) when I was taking these pix. There is a second grease zerk mounted horizontally several inches forward of the zerk shown in the original pix. I still don't know who the manufacturer was/is and the only marking I can find is "M9431 r C", (the "r" being encased in a diamond)(A trademark of some sort??).

My D4 7U has the 2J3454 Bulldozer Support Group with the 2J5440 Push Arm and Brace Group. I determined this by comparing what I have with the Caterpillar FORM UE33731 Parts Book for No. 4S Bulldozers.

Thanks again for all your help!!

OK,
I have that parts manual and that would be a set up for a D4C except the 2J3454 support group does not use and inner support plate (page 14) that we have been talking about. The quadrant support was cantilevered from a single outside brace. Would appear you either have a hybrid:) or an earlier D4 application. Except for the brace we've been talking about your set up looks like regular serial #4A2001-up model 4S to me. (found in form # 30452 4A & 4S parts book)
The serial number plate is probably long gone but check the right side of the rear face of the moldboard near the top for possible stamped numbers.

Here's a picture of the inside support plate that I was referring to: