The New Process can easily be identified by its unique shift cover.
https://picasaweb.google.com/108197707187186692269/DropBox#6270215574163753186I drove a NP541 in a 550 GMC about a half a million miles. The close ratio between 4th and 5th which we called a "working 5th" gave me a big advantage over other trucks of the day. I notice in your photo album you have a ratio chart. If you notice the shift sequence is from 4th low, 5th low, back to 4th high and then 5th high. The close ratios of the last 4 gears allowed me to show tail lights to 409 Chevs with a 370 cu. in. GMC in rolling country. Also 671 Detroits and 250 Cummins with a 10 speed were no match for me because the big gap between 9th and 10th killed them. The goofy arrangement of 1st and 2nd and then the working 5th took some getting used to. But in those days we drove 18 to 20 hours a day and that gave me plenty of practice.
