[rotorwrench]

In 1951, the new diamond tooth gears showed up. If this is a later unit then it likely has those gears. The tail shaft & housing may differ depending on the year of manufacture. The later 259 series transmissions also had their own differences but I don't know if that unit is that late. I'd guess pre 1954 but after 1951 but it could be earlier. I can't really tell with the photos. They should all have the 1-inch 10-spline input but they have different gear teeth than the 49 thru 50 and early 1951. The front bolt up pattern is the same narrow 4-bolt Borg Warner pattern that was used a lot during the late 40s clear up the the early 60s. The early T-10 4-speed even has that pattern.

The forks don't bent easy but they can get that way during an internal failure or under harsh use.