To answer a very popular question, the handle knobs between the Gen1 and Gen2 Fathoms [both single-speed and 2-speed] are interchangeable.
"However", the handle arm is not interchangeable, due to the change in shift mechanism.
Can a gen2 shift mechanism be put on a gen1?
So Alan's knobs should fit on the Gen 2's like they do on the Gen 1's.