So I'm closing the loop on this. I FOUND THE LOCATION FOR THE ROCKERS.
After locating the passenger side rocker with the notches for the weatherstrip retainer in the floor, I moved on to the driver's side rocker, which had no holes left to reference to. The toe board was also gone where the parking brake pedal bracket goes so using that as a reference was a little iffy. After screwing the rocker in place for fitting other parts, I stopped and scratched my head about whether I got it right. I checked against the passenger side rocker measuring from the A-pillar to the large hole for the parking brake shaft (for some reason there is a hole there too.) and found that it differed by about 1/2 inch. Then I went back to the cab dimensions in the FAM and found a dimension at the bend in the floorboard/toeboard. Looking closely at the figure (Sect 1 Sheet 1.07), there was the end of the rocker.
Going back and checking, I was within 1/16 inch of that front of dash reference.
After all that messing around, it would have been simple if I had found that dimension a long time ago. Seems that the holes in the front of the rockers aren't in the same location reference from the front end (my rockers were from two different sources.)
So for you guys who might be at the point of installing new rockers (I know there's a few of you), The end of the rocker should be 8.47 inches to the rear of the face of the firewall. I just clamped a piece of channel to the firewall to measure from.
