The 8RW is a later dip stick for the trucks I think it was used after 52. I don't have my truck chassis parts book at my current location so I'll have to check later to verify.
The overall length of this dipstick is: 22.75 inches and from the flange to the measuring tip it is 14.75 inches. (nominal measurements)
I bought this one because it was advertised as a COE dipstick. That part number is 81W-6750 but the NOS tag on this one was worn and faded and the 'R' looks like a '1'...hence the misidentification. I then discovered that it has an '8RW' stamped on the shaft above the 'FULL' marking.